Sticky #4: Pantera Exhaust Systems

another pic.....

Nice! I am kind of looking around for something to wake the dead with my 417 Fontana Block GT5S, and those look nice. Can't wait to see them on your car. Tips look nice.

Where did you get the tips?

Hello Mike,
I have the same setup installed. I added original ansa tips. I'm interested in your opinion of the sound. We fired the motor before tips where added and it was extremely loud. Didn't realize how much sound glasspack tips control. Mine has a real sweet midrange tone, but I find the sound a bit puffy and soft at low rpm. I'm now experimenting with dual Dynomax race bullets and ansa tips- my take on the old mind train setup.

regards...Mark #3461

Johneye---The tips are Hooker # 22202 Large bore 2 1/2" X 3"

Mark---Im anxious to hear them too. A local guy here dynoed his new 408 and it lost 50 horse with the stock mufflers. I ran my 393 CHI heads engine on a run stand before installation (open headers). Great throttle response. After install with the stock mufflers on I could immediately tell it was choked up. Didnt rev the same. Your vin # is near mine. Is yours originally grabber blue ?

Mike

Nice set of tips!

Yes Mike, mine's originally grabber (french?) blue. Your car being only 21 ahead of mine, might have been part of a blue batch off the line.
regards...Mark #3461

Nice work on the muff's.... I like blue tooooooo

Johneye---The tips are Hooker # 22202 Large bore 2 1/2" X 3

Thanks Mike.

John

For anybody looking for the original Ansa mufflers I did find this source.
http://www.fiatparts.com/ansa-fr.pdf
Take a look a page #9 of that .pdf

And if you are not familure with some of the modifications that can be done to improve the originals you should take a look at this link on the New England Pantera website.
http://panteraownersnewengland.com/big_pipes.htm

John

On the car....

On the car.....

Another one....my bumpers are out being rechromed, cant wait to get them back !!

That looks great!... I second the audio request...

I wish I could post a video/audio. I can only get dial-up at my house, so just posting pics here is a L-O-N-G process. I only ran it for @ 10 minutes in the garage yesterday to cure the paint some. Didnt have time to get it out. It was @ 30 degrees when I took those pics so I closed the garage back up to save my heat. Its loud but I think I can get by with it. Im thinking about making my own version of a Dynatech Vortex Cone to insert into the tips. Anyone ever use those ?

Mike #3482

I made a set of "cones" What a waste of time. Didnt do much. Then I made these repackable inserts for the tips. Packed them with ATV/Motorcycle muffler packing. Excellent ! If I want to be loud...pull em out.

another one

one more

Very cool! Thanks for the pictures.

Mike and Mark,

# 3463 was originally Grabber Blue also. Any chance either of you have the shipper on the car which might have # 3463 on it?

Mike > did your car come from Mike Mayberry? He is a longtime friend of mine here in SoCal and happened to find and originally restore my car 1999-2003.

Dave # 3463 ...the only Grabber Blue left on my car...

My take on the Mind Train. Mandrel bent and fabricated for my car. Gutted Euro cans and gutted tips.

Bang your head and wake the dead...

Dave # 3463

What model no. is the muffler and what are the pipe sizes - look really nice

Dave

My car did come from Mayberry. Since your vin# is close to mine---does your car have the small indicator lights on the dash? Brake warning, etc. I have none and there is no evidence they were ever there???

Mike #3482

Panterapatt

The mufflers are Cherry Bomb Extreme # 545-7425
Pipes, DynoMax 2" mandrel J bends # 289-42310
Tips, Hooker large bore #520-22202
I got everything from Jegs.

The muffler is 2.5 in and 2.25 out so you will need to weld in adapters. I sawed off the muffler where the adapters go so they could be angled up to get that upswept look. The hardest part is getting both sides the same. Nothing worse than crooked tips!

quote:

Originally posted by midenginemike:
one more

How do you keep the tip inserts from being blown out from the pressure?

Mike,

Is the small red light in the center of the pods what you are referring too? I have that.

Mike Mayberry can't wait to see my car completed and here in SoCal. We found several secret messages from him as the car was torn apart. You probably have them on your car too. Check under the console, and attached to the driver's door lock.

Dave # 3463

quote:

midenginemike

Mid engine mike
I am also in the process to manufacture inserts for my "short" PI dampers, they are way too laud for some people, thanks for the picture...
Picture of my stainless system

quote:

And if you are not familure with some of the modifications that can be done to improve the originals you should take a look at this link on the New England Pantera website.
http://panteraownersnewengland.com/big_pipes.htm

John

Good info there. I have Pat Mical's headers on my car, plus mated them to original Ansa mufflers (old style) and welded on SS tips - just slipped them right over the old ones and it worked perfectly. The car sounds incredible -every gear, on or off throttle.

I do NOT like 'loud' but this is just right for me. Very powerful, very strong, but NEVER like a rattly header. When the headers were sent to Roush's shop, the head tech there said they were the nicest built set of headers he's ever seen.

Worth a look. Primaries and collectors larger than any others I found.

Panteradoug--
The outer sleeve is not welded to the inner part between the 10 and 2 oclock position. They fit snug and then bend out the upper portion to make it fit even tighter. It is a straight thru design so there isnt really much pressure buildup. Hope you can make out my explanation......Mike

Dave,

Yes. Im asking about the red "brakes" light. Some have 2 lights between the tach and speedo. Does yours ? Can you measure where the hole(s) need to be drilled and let me know ? The wires are there for the "brakes" light, but I dont see any more extra wires for other lights.

Thanks, Mike #3482

Here's my creation. Dual dynomax race bullets with ansa tips. A bit loud but good sound.

Mike,

1 red light in the "center" of the 2 instrument pods.

My car will be back the week of the 28th. I will measure and shoot a picture for you then.

Dave # 3463

Mike,
Enjoyed seeing what a nice piece of work you have done in keeping the car looking original but at the same time improving it. Looks clean and fits the look of the Pantera. I have been looking at those mufflers myself & even before Cherry Bomb had bought out IMCO's line they were stainless steel. Guess I move to slow.
Very good looking Pantera!

Mark

My exhaust system consists of headers from Pat Mical that have been ceramic coated inside and out silver, by Jet Hot coatings. The collector is a full 3"

The mufflers are a set of Big Bore's that have been flipped up-side down so that the exhaust tips flip up, like European Ansa's. A custom 3" down pipe was fabricated by Kook's Custom on Long Island and the entire assembly was fitted to the car. The back part of the exhaust was ceramic coated black so that it pretty much dissapera up against the chassis. Kook's also provided a set of 4 Corsa custom polished stainless steel exhaust tips.

Wow...This thread sure did draw a lot of interest !! Its great to see everyones ideas and fabrication work. Lets see some more !

Mike 3482

Another muffler gutting:

http://www.spacecitypanteras.com/Technical/Gutting_the_GTS_Exhaust.htm

This Big Throat muffler is now available from PI Motorsports

-G

Show Them To Me!

That opening line is for all you Rodney Carrington fans and connoisseurs

http://www.youtube.com/watch?v=16cWiWj--8E

But since I’m in the processing of fabbing a set of 180s for my Pantera what I’d really like to see in this thread is your 180 header installations and thought it might be beneficial to have a sticky to form a repository of sorts of Pantera exhaust mods and George obliged with pasting in some related threads (thanks G).

Of particular interest to me is the routing of primaries, mufflers used, and choice of tail pipe exit locations.

I’ve committed to do the deed in stainless, using stepped primaries (1.75”-1.875”-2.00”), merge collectors, and straight through packed mufflers. I’ll piece the primaries together from mandrel bends and have a long block and ZF mocked up on a dolley in my shop and have taken the various measurements for routing.

I chose the 6.25” diameter by 17” OAL Burns single stage mufflers over the smaller 4.5” versions. I have 4.5” units on my GT40 and do not find them objectionably loud for my use but because my Pantera is a street car, I thought a little extra attenuation might be beneficial but did not feel the need to go to a the 2-stage muffler, although, there is a version that is dimensionally identical if I ever wanted to go this route. I actually bought the mufflers from Coast Fab because I wanted a couple minor inlet and outlet mods and they fab all of Burns stuff any way. For what it’s worth, they were great people to work with and turned them in 2 days!

I mocked it up first to see how they laid in and what would be possible for routing and exiting centrally in the condenser opening. It became apparent fairly early that I wasn’t as flush with length as I thought since the total stacked length of the turns of the primaries as they enter the collectors, the length of a true merge collector, muffler and tail pipe length, adds up very quickly. I think I’ll need a slight turn down in the tail pipes to exit in the center of the condenser opening as the mufflers begin to interfere with the ZF selector box as shown in the picture.

I must confess that I have a difficult time looking at the rear end of my Pantera without the Ansa style cans, but just can’t stand the performance hit for my state of tune. I plan on making a couple of fiberglass filler panel inserts for existing Ansa muffler cans that allow for easily reversing the mod and swapping back if so desired in the future. It’ll be a slow moving but worthwhile project.

So, show them (your 180s) to me!

I saw this companies website on a post here somewhere, they can make you anything. Ive never called them but they have some very cool tools for the home fab of headers, in the photos section they have a set of GT40 180's, an I thnk they can make any type of collector you want, in stainless or steel.
http://www.stainlessheaders.com/mergecollectors
Jeff

quote:

Originally posted by OSOFAST:
I saw this companies website on a post here somewhere, they can make you anything. Jeff

Yup, they seemed like good guys. I bought mandrel bends, v-band clamps, and various odds and ends from them. They were competively priced and had American milled 304L stainless and had a good selection of 16 gauge. Most folks go 18 gauge but 16 gauge stainless is .062 wall and since I was building step headers stepping twice by 1/8" increments this meant each step nested tightly inside the next making it self-fixturing. The slightly heavier wall and half lap joints will be very strong and TIG up nicely. I figure I gave up 6 lbs going 16 gauge instead of 18 Ga on the primaries but probably a good concession considering the aforementioned.

Their bends were very smooth but the only downside was when I received them they were still full of mandrel lube on the inside. I'll need to have them all vapor degreased before any welding or I'll have a total mess. I'm thinking I'll only have the inside ceramic coated and polish the outside. I'm hoping the inside coating will slow down the heat and rate of oxidation and discloration. I can always re-polish them. I'm just having a hard time bringing myself to putting a coating on a stainless exterior given that I'll have to be crawling all over them.

Best,
Kelly

This is an old shot of the rear on Pantera 4384.
But the exhaust system is still the same.
Headers are ceramic coated.
Rear connector pipes are 2 1/2", (63.5mm) diameter & they go over the driveshafts instead of under.
Nothing touches, has full clearance in bounce & droop.
This makes the pipe slightly longer which helps to muffle the sound a little more & I'm told by my Dyno guy, better to tune.
Stainless mufflers purchased from PI motorsports.
I Tig welded a trangular stainless flange onto the input pipe of the muffler instead of having the slip joint.
The connector pipe spigots into the muffler after the flange so there's no exhaust pressure on the gasket.
This is also done on the end of the headers.
At the rear of the mufflers I Tigged on a mount plate which in turn has a bolt on rubber insulated mount to the chassis to support the muffler weight.

I usually run Mindtrain exhausts but every once in a while, I run these - Dual Flowmaster 40's.

Most of the time, it sits in a box .

Rear view

Kelly,

I am also interested in running 180s on my car and have thought about fabricating a set myself. I ran across this thread a few months ago and found it to be very informative: 180 Header Fab on 400 Swap

I also took some photos of a 180 set-up that Quella's son was installing on a Group 4 car in Castle Rock in March. I'll see if I can find them and post some pics.

GT5 Without Heat Shield

Pic with Heat Shield on GT5. When I refresh the paint on the car, I will shift the heatshield to the decklid so as to better expose the 180s.

Better shot of Detomaso isignia

Who made your headers JT?

The GT5 conversion was done in Glen Pascal's shop in Pennsylvania. Glen has since passed and I do not know who fabed them up.

quote:

Originally posted by Garvino:
Kelly,

I am also interested in running 180s on my car and have thought about fabricating a set myself. I ran across this thread a few months ago and found it to be very informative: 180 Header Fab on 400 Swap

Thta's a good one. I have that thread pasted in my favorites. Hope Brooke's business is picking up so he can resume his build and post here some more.

I'll look forward to the Quella pictures.

Best,
K

quote:

Originally posted by JTpantera: Pic with Heat Shield on GT5. When I refresh the paint on the car, I will shift the heatshield to the decklid so as to better expose the 180s.

Thanks John. Looks nice. I agree, mounting the shield on the engine keeps the weight of the deck lid but is one more thing to remove for service and obstructs the view of that purdy hardware

Best,
K

I have been looking at doing 180's for a long time while planning my build. I have saved about 125 pics of various cars with these set ups from the forum here as well as other places on the net.

If I were to build them I would consider doing a flange between the right and left so you can bolt them up without slip joints.

Also it looks like most people don't have any muffler supports. I would think this would lead to cracks. I was planning on a muffler support bracket using the trans mounting bolts or something.

Now this is nul and void as I am leaning heavily to go 5.0L modular.

Kelly,

Here are a few photos of the Group 4 Pantera that Quella’s son was building in Castle Rock when I was last there. I did not take as many photos of the car as I thought, but hopefully these will give you some more ideas for your 180’s. I do not know who builds the actual 180 headers for Quella’s cars, but I don’t believe they build them in house.

The car was still a long ways from being finished but already looked great. The Group 4 conversion was all steel. On the 180’s, I particularly liked the rear support that Quella had fabricated for the mufflers. Quella’s son also mentioned that the muffler exits would have rings around them when he was finished fabricating the muffler system, etc.

I hope this helps and please keep us posted on your build.

Pic of the muffler support.

Pic of mufflers exiting the car.

Those are georgeous. I love the alignment.

Thanks for those Garvino. That exit and mounting configuration is very similar to what I have in mind. Not much progress but I did manage to get the VBands welded onto my mufflers which was no small task. The mufflers are very light and have a spun end cap that is very thin (like .030"). The extensions are usually slotted and secured with an external clamp. I had to make a stainless spud that fit down in the muffler and into the VBand socket. Even so, it needed a close fitting aluminum plug made to sink the heat and keep the thin walled material from burning away. Turned out pretty good but took some doing. Will have to repeat this on tail pipe section.

Who are some good sources for the various styles of 3" entry stainless tail pipes?

Best,
Kelly

ALEX's Group 4 build has pictures of a nice setup with 180 exhaust. I don't know if he split the tips that way so he can have at least half a trunk or not.

My friend is also running this set up but with the pipes going out the center. The problem with this config is it leaks at the crossover pipes.

quote:

Originally posted by Panterror:
The mufflers are very light and have a spun end cap that is very thin (like .030"). The extensions are usually slotted and secured with an external clamp. I had to make a stainless spud that fit down in the muffler and into the VBand socket.

Kelly,

Nice work as always, can I ask whose mufflers are those and do you have any idea what sort of sound level they will have? With all the CA tracks moving to sound limits I need something to replace the current Ultima mufflers, which are not re-packable.

Thanks,
Julian

this is my next job , making a stainless exhaust. I have now the changed,cut,welded, result of the US installed version . I have the mufflers rotated so to have the tips à la Detomaso "sky" pointing with my ,now, euro style bumpers.( with the US bumper they were horizontal )
What i like visual about them now are the double wall exhaust tips with some sound reducing material in them , further they seem to be "open" ....which give a amazing sound now but ... for driving longer trips it can become "to much" as in terms of speaking with your passenger , phone,radio....sometimes important,alerting,traffic noise .... i would love to get it that bit softer grumble....
Also the steel version now , i got it painted black with high temperature paint , doesn't hold quite well , on some spots it's paint fals of , so i like more the ,even discoulored, look of a stainless one.
I come back here with my project and pics...

quote:

Originally posted by Joules5: ....can I ask whose mufflers are those and do you have any idea what sort of sound level they will have?

They're made by Coast Fabrication. They manufacture the Burn's mufflers and are identical except they tac their logo on instead. Here's a link.

http://www.coastfab.com/mufflers.html

The website isn't particulary instructive and you have to hunt around a bit. I actually found the Burns site to have better visuals. I think prices are the same.

http://www.burnsstainless.com/...a-lightmufflers.aspx

I don't know about the sound level. I have a set 4.5" single stage units on my GT40 and I don't find those objectionable though they may be for some. I went with the 6 1/4" diameter single stage units 3" in & out and am expecting them to be somewhat more mellow than the ones on my 40 although they are a little shorter so we'll see. Coast also has a 2-stage unit that is identical in dimension.

quote:

With all the CA tracks moving to sound limits I need something to replace the current Ultima mufflers, which are not re-packable. Thanks, Julian

Coast will make custom lengths for you at request and pretty much same $ within reason. Your choice of packing. Glass only if you want to save weight or stainless scrubble or mesh if you want more durability.

Best,
Kelly

Well, I can say at long last I’ve had an opportunity to devote some time to the header projects. I’ve done a number of exhaust mods but I can honestly say there is a lot more to fabbing a set of equal length 180’s for a Pantera than meets the eye. Simply stated, there just isn’t much space in a Pantera to route the primaries or even much length for collectors and mufflers for that matter. My GT40 is much roomier. I might have preferred to buy a set, but my combo is C302B heads on 9.5 deck. Twice I have tried vendor supplied headers on my Pantera (ordinary set up for 4V heads on 9.2 Cleveland, and my current set up) that were supposed to be bolt-ons and twice I ended up having to cut and weld. I just got back from visiting with a fellow Pantera owner who is in the process of earning some frequent flier miles his “bolt on” headers too. Nothing against the vendors at all, but my experience says there are no off the shelf bolt-ons for my car. After doing the deed, it’s easy to see why such work is quite pricey to hire. I’ll share a couple of observations for any that are contemplating such a build. You might want to get a cup of coffee or drink.

Vizard says that well designed headers can accomplish the equivalent of 3-4 lbs boost if done properly. ….I’ll have some of that thank you. As a bonus, I dropped my engine off at the builder last week and it looks like the 180s will fit while on his engine dyno……exxxcccccelllent . I expect one of the biggest benefits of going to 180s will be the ability to use zero loss mufflers and eliminate the losses of the GTS style Pantera mufflers though I will miss the look.

So I provided my engine specs and Vince at Burns recommended triple stepped headers (1 ¾-1 7/8 – 2”). He commented they would actually be easier to build than a single diameter non-stepped primary and perform better. I figured what the heck, why not, in for a penny in for pound. The optimal length depends upon your engine specs but in most all cases, the primaries will need to be longer because it’s physically not possible to complete the cross over legs (#2, #3, #6 & #7) at that length. I started targeting 36” length primaries and ended up at 38” length. I just couldn’t get there and found the routing on cross over primaries were the pacing cylinders. This will vary depending upon your layout. I looked at a lot of 180s on Panteras and GT40s. There are lots of ways to get there. I opted for the layout pictured below which causes a rotational, equally timed, firing order around the collector to promote symmetry in scavenging. The fact that I used 6 ¼” diameter mufflers also contributed to the challenge with the crossover primaries because spacing the collectors further apart creates more disparity in length between crossover and non-cross over primaries, so 4” mufflers would help this aspect but be louder as well, especially with only about 13” of active length.
As noted in my previous posts, I opted to mock up the long block and build these out of the car because I didn’t want to take my car out of action for the build (wise move since it’s been a year now), and just couldn’t see crawling around the engine compartment to do this; better off in a chair on the shop floor. It took me as long to establish all the critical/corresponding dimensions and create the mock up as it did to cut and piece all the stainless together!!






I opted for 16 gauge instead of 18 gauge stainless mandrel bends. My first instinct was to save weight and go with the 18 gauge but I went with 16 ga for a couple reasons. Each leg of the primary would nest neatly inside the next making it self-fixturing. I also felt it would be quite strong and this was a plus since 180s grow significantly as they heat and create quite a bit of stress when they do. 16 gauge is also a little more weld friendly. I only give up 6 lbs using 16ga compared to 18ga. I didn’t find that the step headers were easier than a single diameter from a fab standpoint. For one, you need to buy three sizes of mandrel bends. In reality, I did not get to fully utilize the nesting of the tubes in each step transition since the space constraints and routing inevitably dictated that a step would need to occur in a bend rather than a straight section where the tubes could nest. The one thing I would do differently on the routing would be to make the first step from the collectors head for the target area with a 45 degree bend rather than a 90 degree bend. I might have been able to achieve 36” if I did so or perhaps if I routed the crossover primaries first. The first step from collector at 45 degrees would also keep these primaries further from the IR induction inlet air filters. I’ll need to make some shielding to minimize cylinders 4 & 8 from sucking hot air.



A wanted to use a good merge collector to maximize scavenging potential and the recommendation was 2 3/8” merge and cone back to a 3” ring. This is quite a bit tighter than what would be recommended for a normal 4 into 1 but the equal spacing of the 180 firing requires smaller collector area for proper velocity and scavenging. This all adds up to quite a bit of length and if you look at my mock up, you can see it doesn’t provide much space for mufflers and to make the initial turns on the primaries.





With all the effort to plan and fab, I figured it was worth using stainless. Big cost adder but hey, you only go around once right? The most pleasant surprise of the whole process so far was the ability to cut the 304 stainless. After doing some searching, I found DeWalt offered a 12” circular saw blade that they claimed could be specifically used to dry-cut stainless up to 16 ga. I was very skeptical. I found the blade online and gave it a shot. It was recommended to be used at about 1000 rpm. I had a speed control for AC brush motor so I put it to use on my circular saw. It worked OK but was kind of slow going as the speed reduction seemed to be a significant power reduction as well but once you got through the initial cut and broke through the tubing cutting across the two walls of the tube, it went fast until it hit the other side. You could see it would build some heat there. So, for grins, I just decided to try it at full speed rpm. To my amazement, if I applied proper pressure, it blasted right through .062” wall 2” stainless tube throwing a little bit of amber on the initial and final break through. The cuts were fairly clean and square, and each cut only took 3-5 seconds. No odor, and believe it or not, very little heat! I could touch very close to the cut immediately afterward and the cutting part of the saw blade as well? I would then dress the cut tube on the belt sander (also dry) and deburr. I never would have believed dry cutting stainless tube was possible in this manner. I did make some wooden fixturing to clamp and hold the tubes in place for the trickier cuts. Surprising, most of the cuts were quite easy to hold and I did not feel like I would lose control of any pieces holding them firmly against the fence. I did use face shield and ear protection.

I bought a series of the three diameters of mandrel bends in 90s, J-bends and J-45s. Everything I bought was on 3” center line. I looked at three methods of controlling/determining equal length; trial and error, bendable wire of prescribed length, flexible metal hose, and the new fangled modular blocks. I discarded trial and error immediately since I already had an eye watering investment in stainless and wasn’t too interested in a pile of scrap. After I got a good look at the bulls eye I needed to route through, I broke down and bought the “ICE” modular block basic kit which was supposed to be enough to do one side of normal 4:1 headers. Since there was going to be a lot of primary length in 180s and I already had all 3” CL bends, I opted for a custom set that had the majority in 3” centerline pieces since that is what I had in tubing, with 20” of 2” CL and 4” CL, and straight; the rest all 3” CL. I must say, I’m not sure I could have accomplished the routing with any confidence in the equal length without modular blocks. In all, I think the blocks are a clever idea though fragile for metal working environment and a bit overpriced. Nevertheless, I own them.







Now I have to disassemble everything and degrease the tube because although the bends I bought were nice quality tube and bends at a good price, they were also still full of the bending lube, so each segment needs to be scrubbed out with a tube brush in a bucket of degreaser before welding.

I estimate there are about 40 welds to be tigged up. That’s about 240”/20' of bead!! I think this is going to need to be done in two or three steps. The first will be to mark the position of the first step of each primary on the header flange. I think I’ll take a cylinder head and have my bud weld each of these segments first while bolted to the head. Firstly, the head will be a great heat sink and hopefully minimize header flange warpage. If there is warpage, I can correct this while there is still a fairly short and manageable tube length on it. Secondly, I suspect the tube will suck up in a slightly different position and will need to be tweeked with with a bit of bending and/or tweeking on the abrasive belts to keep the butt joints good and tight. I think at the same time, I’ll have a few of the other welds that occur within each step completed and also weld the lugs onto the collectors so they can be used to tighten the primaries into position on the collectors and fixture for final assembly and welding, tuning fit along the way.

Sooooo, anyone want to build a set of 180 degree headers for their Pantera?

Being stainless, they should already reduce heat transfer to the engine compartment. I just can’t get myself to coat the stainless exterior. I like the look of stainless. I would like to coat the interior and will probably use a jet hot distributor and the best thermal barrier possible. Can anyone with firsthand experience recommend a vendor to coat the internals of the headers? A Midwest US vendor is preferred but since it’s only the shipping cost I guess it doesn’t make much difference. It just needs to be someone that knows what they are doing and is willing pay attention to the details.

Best,
Kelly

Kelly,

Very informative posting. Your 180’s look great. I wish I had a set.

Devin

great post Mr Coffield!

I agree, the uncoated stainless has a certain look to it that's very "racy". Great workmanship and attention to detail.

-G

I recall reading an article once about a real GT40 on Hot Rod Magazine a while back. It had a 180 degree exhaust in stainless but it looks like it was anodized yellow. They tolked about wiping down the exhaust with WD40 and heat-cycling inbetween coats. It had a nice look to it. I wish I had a picture of it.

Just a messenger,

Mark


I think, as regards thermal coatings, you get what you pay for. And that
may be in time as well as money. If you search Google under 'Swain Header
Coatings' you will have a ton of hits come up.

I say Swain because back like over 15 years ago that is where I sent our
new headers for #99 after researching it. Wanted the very best heat
retention. I just looked on Google and here is one comment from a user that rings
very true to me.


<< After researching header coatings for several hours, I came to the
conclusion that Swain may be a fair bit better than Jet-Hot as far as heat
retention. I spoke with Dan Swain this morning and my suspicions were confirmed.
I don’t think it is even fair to compare the two products anymore because
Jet-Hot is catering to a different market than Swain coatings.
Swain’s philosophy is to retain heat in the header and keep the engine bay
as cool as possible and damn the looks. Jet-hot is more appearance oriented
and their coatings heat retention properties suffer for it. I liken it to
comparing a great looking pair of thermal underwear to an ugly old fire suit.
If my car catches fire, my main concern is not looking good in my fancy
underwear. Nothing against Jet-Hot mind you, they have a fine looking product
and Swain often refers business to them for their great looks. Conversely Jet
hot refers business to Swain for their far superior heat retention
properties. Bottom line, Great looks = Jet-Hot, Great heat retention= Swain White
Lightning coating.
I had an interesting conversation with Dan Swain and it seems they have
quite a following among people who are familiar with their products but have no
intentions of becoming a national conglomerate. They advertise the
old-fashioned way, word of mouth. They like their relatively small business and
because of that and their popularity, wait times for getting things coated can
be substantial. Their turn around time is about three weeks right now and
that is probably pretty standard I am guessing. I however believe it to be
worth the wait and will be sending my headers to them for what I think is the
end all, be all, keep cool, White Lightning coating. It’s funny, I am really
excited about this coating whereas with Jet-Hot it was “oh well if this is
the best there is, I guess I’ll do it”. On a side note, if you don’t like the
color they come back as, you can use a caned high heat spray coating on
them and it WILL stick and WILL NOT burn off. I just can’t believe no one had
heard of these guys but you have now. By the way they quoted me 275-300 for
the pair. >>


I also remember talking to Dan Swain on the phone back then because I was
hesitating sending the headers all the way to the east coast. If you will
remember, those headers kept the engine bay temps WAY DOWN and we could pull
plugs or re tighten all the header bolts right after a track session. And we
could touch the headers without getting our skin fried. (No pun
intended...Mr. Fry) I know that Swain has a huge following in the Race Community such as
NASCAR because of a superior product.
Here's their web site: http://www.swaintech.com/

Did you design in the ability to partially break down the the system to allow servicing of the transaxle?

quote:

Originally posted by LIV1S: Did you design in the ability to partially break down the the system to allow servicing of the transaxle?

I installed a top fill port for lube on the transaxle in my car a long time ago. In the picture in the post above, it would reside under the driver's side rear muffler. That comes off with removal of the v-band clamp and whatever I come up with to support it at the rear. Other than changing lube, was there some other sort of in-car transaxle service you had in mind?

Best,
K

quote:

Originally posted by ehpantera: I think, as regards thermal coatings, you get what you pay for.............I don’t think it is even fair to compare the two products anymore because
Jet-Hot is catering to a different market than Swain coatings..........Bottom line, Great looks = Jet-Hot, Great heat retention= Swain White Lightning coating.

I had actually used Swain a long time ago but not for header coating. Definitely a high performance barrier coating. They cannot coat internal diameters of long, or winding tubes. I contacted them again to confirm this was still the case. Upon reflection, I dont think it makes any sense to use a cosmetic coating like Jet Hot on the interior. The Swain site caused me to revisit some heat transfer fundamentals and they are correct, there is not much that a .002" thick paint based coating can do in this regard especially considering the minority composition is actually cermaic. It does do a good job as corrosion, heat resistant, cosmetic coating.

The stainless will be somewhat better about lessening heat imparted to the engine compartment, this will easily be more than offset by the additional area of the 180s. Though I'd like to reduce engine compartment temps I dont think I can get myself coat the exterior of the stainless in the Pantera. It's more of a street/show car than a track car. My GT40 on the other hand may be a different story.

Best,
Kelly

So I’ve have made good progress and nearing completion. I decided it would be best to weld the headers up in two stages. First go was to complete any joints within each step, welding on the flanges, and also the collector lugs. In doing so, I figured I could correct any flange warpage while they were still short sections instead of a 36” long snaking tube.





I took an aluminum cylinder head over to my buds place thinking they would be great heat sinks and fixtures for welding on the flanges. It worked great. They all are nice and flat and didn’t have to touch them.




The other thing that worked surprising well was the use of foil tape for fixturing the tubes for tack welding. It has aggressive adhesive and I just applied two or three stripe to each section leaving accessible places for tacking. Simple, fast, and effective.

Having the collector lugs attached allows for pulling down the last stepped segment of the primary into the collector and firmly fixturing it in place.



When you have this many joints, it seems inevitable that things are going to move around a bit after welding so I was concerned they wouldn’t line up very well in the collectors if I did them all in one shot. This allows some mid stream tuning, only two joints with one loose section in each primary to manage and some of these were self fixturing by nesting inside of successive steps. This turned out to be a good move. Five of the primaries went right back in place with only some minor tweaking. The other three were way off. I had to redo a couple joints on the first step of #2, #3, and one on #6. But I got it all fitted up, back together and whole shooting match back over to my buds. He does great work but the welding must come to the welder, not the other way around. I’ll post upon the completion.

Best,
Kelly

So I'm coming down the home stretch.

I mounted the first and third steps of each primary, pulled them down tight and (re)fitted the second step to each primary. I strapped the entire mock up to a hand truck and along with my son pulled it up the hill from my basement shop on New Years Day. I figure the whole thing was about 400 lbs and it was a bit more than I bargained for. Cherry picked it into the truck and then it was back for welding. -I disassemble it to take it back down to my shop.



After tuning of the pieces a bit, I used the same foil tape to fixture the second step of each primary in place and tacked all the primaries while they were on the mock up. Each primary was then removed and welded. The primaries stayed in place very nicely this time and there is definitely a required order of reassembly for the primaries.













So they’re pretty much done though I’ll need to make a good support bracket at the rear of the mufflers. I may get out the buffing wheel and polish them up too. The tail pipes polished up nicely.



Best,
Kelly

Kelly,
Your 180's are the nicest I've ever seen. Quite awesome! That being said and knowing you, I'm not at all surprised. You didn't happen to make more than one set, did you??? If you're looking for exhaust tips, try Fabspeed in PA.

So what's next?

quote:

Originally posted by David_Nunn: Kelly, Your 180's are the nicest I've ever seen. Quite awesome! That being said and knowing you, I'm not at all surprised.

Thanks for that David. Very nice of you to say. You have a high standard and it shows on your car.

quote:

You didn't happen to make more than one set, did you???

Heh, heh. It’s a fairly unique combo. I do have an impressive collection of short stainless straights left over from cutting all the mandrel bends.

quote:

If you're looking for exhaust tips, try Fabspeed in PA.

I took a quick look at their site. They look like a very capable full service shop but I wasn’t able to home in on any tips. I’ll take a closer look later in some of their OE sections. I was just thinking something simple like straight through 3” I.D, 4” OD scrubble packed (maybe repackable?) resonators. The total active length of the mufflers is a little short and I suspect they might be a little on the loud side. Another 6-8” of resonator length might mellow that a bit, especially given they point at the ground. I couldn’t find anything suitable so I was going to roll up a piece of perforated stainless and rollover the lip on the outer piece, but for now, I just stuck the tail pipes on their so I could attend to other matter’s to keep things rolling. Given they come off easily at the VBands, it can be easily attended to at any time before I mode the AC opening cover.

quote:

So what's next?

Building EFI looms, sourcing fuel system components, and completing induction system air flow components. I’ll need to do a little work to isolate the rear cylinders from exhaust heat. When I get to install, I’ll need to come up with some inserts or novel treatment for the vacant mouse holes where the Ansa cans use to reside. My current thinking is to keep the mod reversible.

The Fontana Engine is at Dave McLain’s shop and is just going back together now. He has one of the water brake style dynos and can accommodate the headers being installed while testing so that’s kind of a nice fringe benefit.

Take care,
Kelly

Beautiful work Kelly.

Considering the recent improvements in the ceramic coatings available, I seriously doubt the need and desirability of building headers in stainless?

I had mine coated inside and outside and the coater has flow bench numbers that show the headers flowing a lot better coated inside.

I have seen several stainless sets recently and they turn all sorts of colors in usage. Cosmetic stainless, 303, 304 always had the reputation of splitting from the heat.

I already know it is very difficult to bend without kinks and ripples and it isn't that simple to weld.

Something to think about?

quote:

Originally posted by PanteraDoug: Beautiful work Kelly.

Thanks Doug, much appreciated.

quote:

Considering the recent improvements in the ceramic coatings available, I seriously doubt the need and desirability of building headers in stainless?

Does anyone really need a stainless exhaust system? Just depends on what you want out of them. Certainly more expensive but if offered the choice between a mild and stainless steel exhaust system I can’t imagine why anyone would choose mild steel.

quote:

I had mine coated inside and outside and the coater has flow bench numbers that show the headers flowing a lot better coated inside.

Other than cosmetics, there’s really no need to cosmetically coat mild steel headers either. As discussed earlier in this thread, they’re great cosmetic coatings, but after Mark (ehpantera) posted earlier, I revisited a little basic heat transfer and quickly concluded the heat reduction claims of the paint based cosmetic ceramic coatings are greatly exaggerated. As far as flowing better, don’t want to burst your bubble but I seriously doubt there are any material gains to be had. IMO, that’s mostly marketing BS that goes along with the claims of reduced heat transfer equating to higher velocity hot gas flow. Sure, the theoretical argument is sound but in practice is not material. It’s not like a cast iron exhaust manifold. The inside of a mandrel bent tube is already pretty nice surface and even extrude honing won’t do much to the welds as far as flow losses go.

quote:

I have seen several stainless sets recently and they turn all sorts of colors in usage.

Virtually all bare metals (at least the ones you would use for an exhaust system) will discolor to varying degrees depending upon the metal and usage temperature.

quote:

Cosmetic stainless, 303, 304 always had the reputation of splitting from the heat. I already know it is very difficult to bend without kinks and ripples and it isn't that simple to weld.

Not sure what you mean by 304 being cosmetic stainless. You see it used in a lot of cosmetic applications because in annealed state 304 is fairly easy to cold work as far a stainless steels go. It’s certainly not Inconel or even 321 but it is a true austenitic stainless steel. It’s 18% Chromium and 8% Nickel. Some folks still refer to it as 18/8. I used 304L which is typical for applications that will be welded because of lower carbon content the post weld heat treatment recommended on 304 is not required. As far as weldability, the guy who welded it says it’s very easy to weld compared to say aluminum which tends to puddle and flow all over the place.

The biggest reason for using austenitic stainless (other than avoiding rust) on a performance automotive exhaust system is that it retains its mechanical properties at elevated temperatures and only conducts heat at about 1/3 the rate of mild steel with thermal conductivity 16 versus 43 W/m.K. By way of comparison, Inconel is 14W/m.K in similar temperature range. Tell-ya-what, I’ll put that up against the heat transfer reduction afforded by paint based ceramic coatings on mild steel. I could really tell when I was cutting and using abrasive belt to fit the stainless pieces. You can get a localized area at the tip of the tube red on the belt and you can still touch near the point for quite a while before the heat is conducted up the tube.
Normally aspirated cars are not as hard on exhausts as turbo cars. If this was a turbo header, I would likely have used 321. Mild steel headers are typically short lived in on turbo cars (at least the header to turbine part). Strength at temperature is why lighter gauge material can typically used on stainless exhaust systems. I opted for 16 gauge because the heavier gauge bends more easily in tight radii and the price of bends reflected this. It was only an additional 6 lbs using 16ga vs 18 ga on the primaries.

Bottom line for me on this was given the amount of effort to plan and fabricate, with any reasonable valuation of time, it made sense to use the most durable material. It will handle the heat mechanically and be a very durable life-time exhaust system. It will also significantly reduce heat transfer and yes, will oxidize, but can be repeatedly re-polished if so desired. It’s a matter of taste but I like the look of stainless. Some guys on the GT40 forum wipe their stainless down with WD40 because it produces a more golden oxidation layer similar to Inconel. I haven’t decided how or if I’ll finish the surface.

Best,
Kelly

Personal taste is one thing but cost hasn't been discussed as a factor. If it is cost no object then who can argue? I am the original stainless guy.

I have a picture of the stainless headers here somewhere on the continuation Mark IV GT40s that were at VIR SAAC convention.

The color variation I saw now that you mention it must be oxidation. Looked a little like someone was polishing out their ss kitchen sink with SOS pads?

I had my 180s coated by Connecticut Coatings. They have their own blend of color which they say is their exclusive color. The coat fully inside and out, then polish them. They look a lot like a mill finish stainless. The color dosen't change.

The exit for the mufflers is in the stock Pantera location like the G4's were. Mufflers are polished 3" core full stainless bullet packs. Saves me a lot of time in reinventing the wheel.

They did the Hooker Comps on my 68 GT350 and when I find a set of headers that fit the 67 GT500, will go that route with them also.

My knowledge of stainless tubing is limited to 409 and 304. Afterall this is the NYC area and it is a veritable technology waisteland. You can't find anything here. Everything I need comes from the Midwest.

The only thing we have here is welfare, bankers and wall street tycoons. It isn't even children and women first, it's everyone for themselves from the start?

No one here knows WTF I'm talking about at all. Might as well be from Mars. Personally I'm from Zluto...but that's another story altogether?

Good luck on the Pantera. Looks fantastic. Hope you finish it someday? LOL!

quote:

Originally posted by PanteraDoug: Personal taste is one thing but cost hasn't been discussed as a factor. If it is cost no object then who can argue? I am the original stainless guy.

If price was no object they would be Inconel or Ti.

Ya-know, the difference between stainless and mild steel may not be as big as you think. Most of the decisions I made on my system that increased cost had nothing to do with material choice but I’m certainly pleased with those decisions.

I bought about $900 worth of stainless mandrel bends. If I did it again, I could do it in $750 easy. If I didn’t have three steps in diameter, probably $600. So do you want stepped headers or a single diameter primary? In general, in 16 ga, I’d say mild steel is about half the cost of 304L unless you’re buying from Burns. Anyway, mild steel saves you somewhere between $450 and $300 on the primaries.

The next big ticket item is the collectors. Do you want the performance of a true merge collector with the ease of assembly of slip joints or just a formed collector with no bullets? I bought stainless slips for $400 a pair (Burns were $800). You can buy a pair of formed collectors for $100. $200 if you want bullets. It’s all a trade on fab labor, your own skill level, and how you value your time. You don’t see many true merge slip collectors in mild steel because no one would bother to invest the time. Anyway, this is a $300 difference but it’s really driven by the choice collector style and degree of fab, not the material. So even though it’s $300 delta in cost it’s not a fair comparison because a simple open formed collector will not do what a merge collector will do performance-wise.

Flanges are also pricey. I paid a friend of mine to machine 8 pieces of 304L to my specs and it was $280. They were high port pattern but I suspect I could have gotten mild steel somewhere for half that somewhere.

The rest of my system is also purely choice but really not much to do with material.

I chose VBand clamps over flanges because of ease of service but a flange and gasket works just as well. I chose repackable light weight stainless mufflers but could have put a $60 mild steel glass pack on each side. Maybe they could be done in stainless for double that?

Anyway, the fair comparison of materials is at the primaries, and I think that is $900 vs $450 (but this might only be $600 vs $300 in a single diameter header). For the collectors its $400 vs $100, but as I said, still not apples to apples performance-wise. Another $150 for the flanges so maybe $1580 vs $690; stainless versus mild steel. $900 delta maybe?

Wouldnt have done me any good but I think you can buy a set for mild steel 180s for 4V Cleve heads on 9.2 deck from Hall for about $1100. That's the difference between someone who has done the layout work and has a CNC bender and inexpensive long mild steel sticks and someone that has to piece together mandrel bends. IMO they’re beat to fit and paint to match as a friend of mine says. If you hired someone to have set like I made in stainless, I think you’re talking North of $5k and >$3k of this would be labor. Dont see how someone could do it for less.

I can’t tell you how many hours I have invested in researching parts, design and planning the layout, but it’s way more than the fab time. It’s so fun for me it’s hard to consider it as cost. When it got down to the actual fab, I think I maybe had two full, solid weekends into it and I hired the welding.

I dunno, I just wanted the set of headers that was in my mind's eye. When it comes to cars, some things you just need to do and not grind too much about the dollars or the time. What else would we be doing?

Best,
Kelly

quote:

Good luck on the Pantera. Looks fantastic. Hope you finish it someday? LOL!

You eat the elephant one bite at a time. It will be done!

Best,
K

Kelly my friend, you've done well.

Can't wait to hear it & see it in person some day.

-G

Must be the difference in where we are located? Those bends are about $30 each to me. At least that's what I was quoted?
I had two 3" to 2-1/2" stainless reducers made for me and they were $35 each.
I figure I would need about $3500 to buy the stainless necessary to build those headers.
When you are in NY, you ream them good?
Is Iowa really part of the US or is it NY is just in a different Universe? No matter. I'm stuck here. Wanna' see expensive? Forget Beverly Hills. Come to NYC. Fireman make $100,000 a year here. Cops retire with $200,000, a year pensions. No matter on which is real and which is screwed up. Effect is the same?

quote:

Originally posted by Cowboy from Hell: Kelly my friend, you've done well. Can't wait to hear it & see it in person some day. -G

Thanks G.

I think I had one too many glasses of liquid sedative last night. I could have called it a night if I just said I figured I could buy all the stainless from the heads to the VBands for the same price as buying the Hall 180s (even though not available for my combo), having them coated, and shipped twice.

Best,
K

quote:

Originally posted by PanteraDoug: Must be the difference in where we are located? Those bends are about $30 each to me. At least that's what I was quoted? Is Iowa really part of the US or is it NY is just in a different Universe?

It's not Iowa, just e-commerce man! I bought most of the stainless bends from these guys. It was all 3” CL and all US milled Rath-Gibson tube.

http://www.stainlessheaders.com/mandrelbends

I bought a few of the exceptionally tight radius (2” CL) pieces from these guys. It wasn’t quite the quality of the above. I’m not sure it’s a fair comparison given the tight bending radius but the tube just wasn’t the quality form the above source. They carry a lot of Vibrant brand stuff which is usually decent quality. They have lots of related hardware and I found their website quite user friendly and complete with information.

http://www.verociousmotorsport...-Steel-Mandrel-Bends

These guys are also quite reasonable and good quality.

http://www.mandrel-bends.com/catalog/

All of the above are still full of mandrel lube. I bought a long tube brush for $3 and $3 worth of water base degreaser concentrate in a 5 gallon bucket. About 2 minutes in the bucket with the brush was all it took to make the pieces look bright dipped.

I’ve mentioned Burns a couple times. I don’t mean to bag on them in anyway. Their quality is first rate and the stuff comes clean, degreased, and individually wrapped. I just can’t justify 75%-100% more in price for it.

-Your results may vary.

Best,
K

I can understand and support your enthusiasm for engineering, building, and installing the headers yourself.

After all, you even engineered your own intake manifold and FI system?

I realize also the satisfaction you will have when it is done.

Trust me...I get it.

Beautiful workmanship Kelly! The best I have seen. I am inspired.

Johnny

This is just an amazing exhaust system!! Congratulations on the quality of the work.

Has anyone made a tri-Y header system that comes out over the transmission like these 180's do?

quote:

Originally posted by Panterror:
So I'm coming down the home stretch.

I mounted the first and third steps of each primary, pulled them down tight and (re)fitted the second step to each primary. I strapped the entire mock up to a hand truck and along with my son pulled it up the hill from my basement shop on New Years Day. I figure the whole thing was about 400 lbs and it was a bit more than I bargained for. Cherry picked it into the truck and then it was back for welding. -I disassemble it to take it back down to my shop.



After tuning of the pieces a bit, I used the same foil tape to fixture the second step of each primary in place and tacked all the primaries while they were on the mock up. Each primary was then removed and welded. The primaries stayed in place very nicely this time and there is definitely a required order of reassembly for the primaries.













So they’re pretty much done though I’ll need to make a good support bracket at the rear of the mufflers. I may get out the buffing wheel and polish them up too. The tail pipes polished up nicely.



Best,
Kelly

Forgive me for asking, probably going to sound like a stupid question. How do you manage to get those on the engine once the engine is in the car? It just does not look like there would be enough room to install them.
BTW huge fan of the work, they look great!!

quote:

Originally posted by Quickitty:
Forgive me for asking, probably going to sound like a stupid question. How do you manage to get those on the engine once the engine is in the car? It just does not look like there would be enough room to install them.
BTW huge fan of the work, they look great!!

Each primary seperates and can be installed individually. Then you install the collectors, then mufflers. It's really not too bad and in some respects easier than conventional 4:1 headers beacuse you are only handling one tube at a time. However there is a specific installation order for the primaries that needs to be followed due to how they nest.

Best,
K

These are really a beautiful set of headers. Really nice job. Great welds.

I saw headers like this on the Holman-Moody Ford Mark IV continuation cars. They were not polished out. They had a nice golden tone to them.

As far as a support bracket remember that these headers move quite a bit when torquing the engine.

The supports will need to be flexible. I think this is why the GT40's use the "screen door" srings wrapped around the exhaust pipes?

I think if you don't do that you will stress the headers out at some point?

How close to equal lengths were you able to get the primaries?

quote:

Originally posted by PanteraDoug: These are really a beautiful set of headers. Really nice job. Great welds.

Thanks Doug. I hadn’t looked at this post in a while.

quote:

As far as a support bracket remember that these headers move quite a bit when torquing the engine…..The supports will need to be flexible. I think this is why the GT40's use the "screen door" springs wrapped around the exhaust pipes? I think if you don't do that you will stress the headers out at some point?

Yup. Mounting must allow for dimensional change at temp.

quote:

How close to equal lengths were you able to get the primaries?

You can take a string or wire and measure the path 180 degrees apart down the length of the primary but it’s hard to do with all the snaking around. I used those orange building blocks for the layout and faithfully reproduced the segments in stainless bends which is probably about as accurate as trying to measure them. I’d say probably +-1/2” over nearly three feet of primary…and if so, that’s +-1%. All of the above only holds true if the exhaust pulse travels the centerline of the primary which is optimistic, what what else would you figure? –Close enough for Rock & Roll. They sound good and and were good for about 25HP over the best set of dyn headers and mufs in the shop. Hard to say how much better they are than PCar stockers but with the solid cam I'm running, I'd say a bunch compared to that.

I’ll have to post some pics of them on the engine on the dyno.

Take care,
K

quote:

Originally posted by Panterror:

quote:

Originally posted by PanteraDoug: These are really a beautiful set of headers. Really nice job. Great welds.

Thanks Doug. I hadn’t looked at this post in a while.

quote:

As far as a support bracket remember that these headers move quite a bit when torquing the engine…..The supports will need to be flexible. I think this is why the GT40's use the "screen door" springs wrapped around the exhaust pipes? I think if you don't do that you will stress the headers out at some point?

Yup. Mounting must allow for dimensional change at temp.

quote:

How close to equal lengths were you able to get the primaries?

You can take a string or wire and measure the path 180 degrees apart down the length of the primary but it’s hard to do with all the snaking around. I used those orange building blocks for the layout and faithfully reproduced the segments in stainless bends which is probably about as accurate as trying to measure them. I’d say probably +-1/2” over nearly three feet of primary…and if so, that’s +-1%. All of the above only holds true if the exhaust pulse travels the centerline of the primary which is optimistic, what what else would you figure? –Close enough for Rock & Roll. They sound good and and were good for about 25HP over the best set of dyn headers and mufs in the shop. Hard to say how much better they are than PCar stockers but with the solid cam I'm running, I'd say a bunch compared to that.

I’ll have to post some pics of them on the engine on the dyno.

Take care,
K

One race header builder that I know, "cc's" the tubes!

I think if you can get them within 2" AND be able to get them on and off the car, you are an over achiever.

I don't know exactly how close the GT40 tubes were on the race cars but if they were within 2" I'd be shocked?

Nice job.

quote:

Originally posted by PanteraDoug: One race header builder that I know, "cc's" the tubes!
I think if you can get them within 2" AND be able to get them on and off the car, you are an over achiever.
I don't know exactly how close the GT40 tubes were on the race cars but if they were within 2" I'd be shocked?
Nice job.

Thanks Doug. As far as I know exhaust tune is a function of harmonics which is modeled by wave theory. The operative factor in doing so is length of the primary. I had never thought about cc’ing a primary. I have my doubts whether volume would be a better predictor of length traveled by the wave of the exhaust pulse. The cross sections of even mandrel bent tubes aren't consistent enough and as I previously mentioned, I doubt the pulse feels compelled to travel the centerline of the snaking primary, but to the extent to which volume predicted length more accurately it could be helpful.

I do think the volume can be a predictor of the gas velocity and mechanical efficiency or losses, but the pressure wave is sonic.

If I was racing on TV on Sunday afternoons it might matter. My Pantera will never know the difference even if I did

Take care,
K

I think the consideration in cc'ing the tubes is exactly what you were saying about the "effective length" of the primaries?

The guy who was teaching me head porting was telling me that parts of the intake port have little or no effect in increasing the volume of mixture able to flow within a given time period.

He also thought that the short turn radius into the valve pocket was the most important and used the analogy of a water fall as what he thought was happening there.

He thought that if the radius was correct that the mixture would flow like a liquid would at that point so the radius of the turn was very significant to the flow. The flow should be treated as a liquid would at that point.

Certainly harmonics can be heard in the intakes as well.

Exactly what is happening in the exhaust probably has similarities to those thoughts but if the current thought of modeling is that the harmonics are what is being tuned, who am I to argue?

Certainly the harmonics of the GT40's at Daytonna in '65 in the distance is what I noticed on the "bundle of snakes" exhausts they were running.

The Cobras would run by with an entirely different sound. The sound of the GT40 exhaust in the distance was unmistakable.

It was said at the time that the exhausts on the "40's" was thought to be worth about 100hp over the Cobras.

It's also interesting to me that the length of those primaries tuned the 289 to be all in at about 5,500 rpm? They certainly were being turned much higher then that.

I got "yelled at" by a couple of "vintage guys" that still work for Holmon-Moody, that the engines, at least in the case of the 427's, was strictly limited to 7,000 rpm, because of the limit of valve spring technology at the time. This for an engine that every other component seemed to be built for over 8,000 rpm's?

That certainly isn't the problem these days at all.

There weren't many shops back then with chassis dynos and if you think about it what the head porters were doing was copying "models" that they knew improved performance. The terminology hadn't been coined yet then to explain it.

Now everyone who has a software program that works with this can essentially design a profile that can be cut on a CNC machine and maximize for the criteria desired.

I think though that there will still be debate over whether the engine should be tuned for peak hp or maximum hp increase under the curve?

I tend to think for peak hp?

FWIW, engine builder & author David Vizard has written about headers several times in his various books, and according to his dyno tests, if the individual tube lengths are within about 6" or so, no power gains/losses will be seen. What's more important is the fit of the individual tubes into the weldment. Sloppy tube fits buttered up with weld do not work as well as neat fitting 'fishmouth' tubes, and often crack. Further, mild steel tubes will expand and contract by as much as 0.060", and stainless even more, which is really what cracks poorly made headers.

quote:

Originally posted by Bosswrench:
FWIW, engine builder & author David Vizard has written about headers several times in his various books, and according to his dyno tests, if the individual tube lengths are within about 6" or so, no power gains/losses will be seen. What's more important is the fit of the individual tubes into the weldment. Sloppy tube fits buttered up with weld do not work as well as neat fitting 'fishmouth' tubes, and often crack. Further, mild steel tubes will expand and contract by as much as 0.060", and stainless even more, which is really what cracks poorly made headers.

I'm not arguing and actually like that statement.

Putting headers on my Shelby, I wound up with a choice of Hooker Comps or Super Comps.

The Comps are not equal length. The Super Comps are.

Hooker claims the difference is 3% at the top.

In my case the difficulty of installation with the equal length increases exponentially.

Equal length were 34", the unequal short tubes were 32", long 34".

I'll go with Vizard. I like the guy already.

Hi all, this i my first post, my name is lyle and i'm from Sydney Australia. I don't have a Pantera but my car does have a 351c and this is what attracted me to this forum.

I've often wondered about this "equal length" primaries business with extractors. I know there is a sonic issue with pressure waves moving at the speed of sound and equal lengths are thought to be beneficial with this concern but i wonder if most engines would ever be used at the consistently high rpms to really justify it.

I was thinking that for most engines what you really need rather than equal length or equal volume, as mentioned earlier in this thread, is in fact equal flow.

Looking at a set of extractors with equal flow in mind you would actually not have equal length primaries anyway.

Imagine the pipes from the front cylinders of the engine, they tend to be long and straight with only slight bends, the pipes from the rear cylinders are bent and contorted in every which way like a angry sidewinder just to squeeze in enough tube length so they are as long as the front tubes.

But a bend in a piece of tube creates friction as gas flows through it. So 12 inches of tube with a 90 degree bend in it
may act as if it is 24 inches of straight tube.

This means those rear pipes with a bunch of wild bends in them to get them the same length as the long front pipes in fact could be much shorter and have less radical bends in them. A kind of balance between bend degrees and tube length would need to be found. Ideally rather than check the pipes volume the pipes need putting on a flow bench.

I guess you can theorize for ever over this sort of thing but the bottom line is you've got to have some pipes that will fit into your car. The theoretically perfect pipes are useless if they won't go into your engine bay. [IMG:left] [/IMG]

[QUOTE]Originally posted by Aus Ford:
Hi all, this i my first post, my name is lyle and i'm from Sydney Australia. I don't have a Pantera but my car does have a 351c and this is what attracted me to this forum.

I've often wondered about this "equal length" primaries business with extractors. I know there is a sonic issue with pressure waves moving at the speed of sound and equal lengths are thought to be beneficial with this concern but i wonder if most engines would ever be used at the consistently high rpms to really justify it.

I was thinking that for most engines what you really need rather than equal length or equal volume, as mentioned earlier in this thread, is in fact equal flow.

Looking at a set of extractors with equal flow in mind you would actually not have equal length primaries anyway.

Imagine the pipes from the front cylinders of the engine, they tend to be long and straight with only slight bends, the pipes from the rear cylinders are bent and contorted in every which way like a angry sidewinder just to squeeze in enough tube length so they are as long as the front tubes.

But a bend in a piece of tube creates friction as gas flows through it. So 12 inches of tube with a 90 degree bend in it
may act as if it is 24 inches of straight tube.

This means those rear pipes with a bunch of wild bends in them to get them the same length as the long front pipes in fact could be much shorter and have less radical bends in them. A kind of balance between bend degrees and tube length would need to be found. Ideally rather than check the pipes volume the pipes need putting on a flow bench.

I guess you can theorize for ever over this sort of thing but the bottom line is you've got to have some pipes that will fit into your car. The theoretically perfect pipes are useless if they won't go into your engine bay. [IMG:left][url=http://s1252.photobucket.com/user/Aero_9000/media/shed002s.jpg.html][/QUOTE


One thing I know is that the direction of the first section of tube is important.

If you notice that the first turn on Kellys pipes is up rather then down, this was shown on dyno tests to increase the flow of the exhaust ports.

On the iron 4v heads to accomplish this you really need to do something like was done on modifying the exhaust ports on the Pro Stock engines.

This is one area where the "high port" Cleveland heads is superior to the original Ford iron head exhaust port configuration which turns them down. The 2v ports simply can't be made to flow equal to the 4v ports in any configuration.

The 2v iron head is worse then the iron 4v in that respect.

That's one reason why the 3v heads, 2v intakes with 4v exhausts are popular.



In the Pantera the 180 degree header configuration compliments that flow increase potential by running up and over.

This is also an area where the Windsor port heads can't compete with the Cleveland heads.

So there are two advantages going on here, the first turn up of the exhaust, and the direction of flow up of the exhaust in the aluminum high port head.

When I first put the A3 heads on my engine, it was thought by the engine builder that it was simply about a 30hp advantage over the iron head?

If you notice, there are quite a few C3 head engines that are running around the streets with dynoed engines in the 700hp range vs. the 550hp range of the iron heads?
The head configuration and exhaust combinations are allowing for more then that 30hp initial difference.

Ron McCall just built one (the white Gp4 car) for a customer that shows around 750hp



The size of the tube, and the length of the primaries becomes a tuning device to put the maximum power at one particular rpm or in one power range.

A car with a conventional configuration of exhaust piping, turning down, is going to be at a hp disadvantage.



I suppose you could say that the identical engine in a different chassis then the Pantera is not going to make the same power because of the exhaust limitations of it vs. the exhaust configuration advantages of the Pantera.

I think that was shown years ago when Ford was running the 289 in the Cobra and in the GT40 and the GT40 made 100hp more because of the exhaust configurations available.



The original exhaust configuration of the Pantera of the headers "under" the chassis is because of the desire for the car to have a real rear trunk.

In the case of the original Pantera exhaust, it made less power then in a car like a Mustang because of the size limitations on building a set of headers long enough to have a set of working collectors.



There you have to go back and use the original Ford racing recommendations of a 2" primary tube, 36" long primaries, with a 3-1/2" collector 6 to 9" long (tunable) for maximum power.

The inside diameter of the exhaust primary should be about equal to the outside diameter of the exhaust valve, which is where the 2" primary tube size came from.

That may help compensate for "frictional losses" within the header? I doubt that these 180 headers are suffering much at all?



I have never seen a set of "under" car headers in a Pantera built close to those dimensions. They just won't fit with any kind of a muffler system?

Sure the harmonics are involved in this. You can always hear the difference in the harmonics of the exhausts on the race track. The cars that have noticeable more power have a higher pitched sound to the exhausts.

I think of it as similar to a trombone where the musician operates the slide to achieve the different notes. As a header builder, you are looking for a certain note.


Kelly's headers are a close attempt at maximizing all of these considerations and will no doubt play a mesmerizing concerto.

Kelly's headers are a close attempt at maximizing all of these considerations and will no doubt play a mesmerizing concerto.[/QUOTE]


Those pipes are absolutely amazing ! Superb !

quote:

This is one area where the "high port" Cleveland heads is superior to the original Ford iron head exhaust port configuration which turns them down. The 2v ports simply can't be made to flow equal to the 4v ports in any configuration.

The 2v iron head is worse then the iron 4v in that respect.

That's one reason why the 3v heads, 2v intakes with 4v exhausts are popular.

I'm a little baffled by this. I've been hearing for years that the 2v exhaust port actually flowed better than the 4v exhaust port. The opposite of what you are saying ??

Not to my knowledge, but I could be wrong.

The 2v heads have a torque advantage at lower engine rpm's due to the smaller port area cross sections.

I've seen them run very well on 302's also.

The 2v heads are also pretty much limited to a .500" lift cam. They simply stop flowing over that.

In order to make 500hp out of 351 inches, you need around a .600" lift with 4v heads too...but this is kinda sidetracking this thread isn't it?

quote:

I'm a little baffled by this. I've been hearing for years that the 2v exhaust port actually flowed better than the 4v exhaust port. The opposite of what you are saying ?

4V heads flow better without a doubt! As Doug pointed out, 2V heads are purported to make more low end torque and offer snappier throttle response and off idle performance in a street driven Cleveland because the smaller intake ports allow for higher air/fuel mixture velocity at lower RPM's. But 2V heads will not outflow 4V heads!

More info on heads from Dan Jones at this link:
http://pantera.infopop.cc/eve/...700067562#9700067562

quote:
This is one area where the "high port" Cleveland heads is superior to the original Ford iron head exhaust port configuration which turns them down. The 2v ports simply can't be made to flow equal to the 4v ports in any configuration.

The 2v iron head is worse then the iron 4v in that respect.

That's one reason why the 3v heads, 2v intakes with 4v exhausts are popular.



quote:
I'm a little baffled by this. I've been hearing for years that the 2v exhaust port actually flowed better than the 4v exhaust port. The opposite of what you are saying.


quote:
4V heads flow better without a doubt! As Doug pointed out, 2V heads are purported to make more low end torque and offer snappier throttle response and off idle performance in a street driven Cleveland because the smaller intake ports allow for higher air/fuel mixture velocity at lower RPM's. But 2V heads will not outflow 4V heads!



posted August 30, 2009
quote:
The 4V exhaust port is an oddity of the Cleveland design, something we uninformed masses will scratch our heads about forever. Consider that the 2V head was an afterthought, it was designed by the same engineers who designed the 4V head but it has no gas bounce trickery in the exhaust port. The 2V exhaust port out-flows the 4V exhaust port measured in the conventional manner on a flow bench. But the 2V head does not have the same potential as the 4V head. I think the flow bench is a good tool for measuring the results of porting work, or for comparing one head to another, but it does not measure the head under dynamic conditions, with a piston going up and down in the cylinder, valves opening and closing, and combustion taking place etc etc. The engineers at Ford had dynamic potential in mind when they designed the 4V intake and exhaust ports. I guess the exhaust port design just didn't pan out as well as the intake port in real world use.


So which exhaust port flows better ??

Here's the numbers



That was me you were quoting. My comments weren't 100% accurate were they? The 2V exhaust port flows well on the bench, but it doesn't really out-flow the 4V exhaust port. Comparing ported heads, the numbers are quite equal up to 0.500" lift, then the 2V port predictably flattens out while air flow through the 4V port keeps on increasing.

If you wish to further discuss exhaust port flow, please start a new thread, do not take this thread further off-topic. I'll gladly move these last few posts to the new thread. And please keep it friendly and respectful.

-G

Thankyou George for clearing up the issue, no need for a new thread and no disrespect intended i was just confused by contradictory posts.

You have a very good knowledge of the Cleveland, have you written any books on the 351c ?

quote:

Originally posted by Bosswrench: FWIW, engine builder & author David Vizard has written about headers several times in his various books, and according to his dyno tests, if the individual tube lengths are within about 6" or so, no power gains/losses will be seen.

Actually, if you are referring to his writings in his “Building Horsepower” series, when Vizard made this statement it was specifically in reference to dual plane crank V8s and conventional 4-1 headers. This is due to the asymmetry in how the exhaust pulse phasing arrives at the collector in a dual plane V-8. Though dual plane V8s with 4-1s are relatively insensitive to primary length, they can be very sensitive to collector diameter and collector length. In fact, collector length can be a very (if not the most) effective parameter in tuning such a system once the in car constraints and layout is fixed. When you go to 180 degree exhaust in the same V8, equal length primaries certainly does matter. However, this whole discussion must be footnoted with the fact that it is most often the case that it is impossible to achieve the theoretically optimal primary length because you physically cannot make equal length primaries reach the collectors without adding additional length. This is certainly true in Pantera’s and GT40s. The most popular embodiment for dual plane V8s remains the 4-2-1 or the Tri-Y, as most commonly seen in NASCAR. When done properly, they are very long for Pantera fitment though possible. The good news is you can still build a high performing zero-loss exhaust system within the constraints of a Pantera.

quote:

What's more important is the fit of the individual tubes into the weldment. Sloppy tube fits buttered up with weld do not work as well as neat fitting 'fishmouth' tubes, and often crack. Further, mild steel tubes will expand and contract by as much as 0.060", and stainless even more, which is really what cracks poorly made headers.

In the same articles, Vizard also comments that 4-1 Dual Plane V8s are remarkable insensitive to dents in primary tubes, with sometimes no noticeable performance effect with even 60% of the diameter compromised. So all you sledge hammer mechanics rejoice.

Best,
Kelly

quote:

Originally posted by Panterror:
So all you sledge hammer mechanics rejoice.

How about something different:

[img]

It sure is different.

LOL, tactful response.

strange and mind opening ! Clever idea... but is it all worth that piping performance wise ??

I purchased a set of Pat Mical headers and the joining pipe to the rear muffler. 3" collector which tapers down to 2.5" on mine and then v-band clamp to the mufflers. I did have some very noisy twin pipe mufflers that the fiberglass muck just continued to come out of. These are not from Pat or the ones he uses.


Pat Mical has modified a pair of my Hall Pantera euro Ansa mufflers that I had. He had to cut and then drill out where the old pipe came in and he welded a 2.5" stainless pipe in there with a v-band connector. Looks very nice and a lot quieter.


Pat also knocked out the plug that was at the very end of the perforated tube.

I hope I get to hear it at the tutto!

Is anyone running the PI Motorsport pipes? If so, how do you like them?

For something as coveted as ANSA mufflers, it continues to puzzle me why used, beat up relics continue to sell on Fleabay when Steve offers such a nice set. That said, I have seen literally zero marketing of his setup. Does anybody have any pictures of them installed?

how loud are Wilkinson's new ansa style mufflers? I'm wondering how much louder they are than the stock ansas...

quote:

how loud are Wilkinson's new ansa style mufflers? I'm wondering how much louder they are than the stock ansas...

While I don't have a before and after DB number, I can tell you that they are definitely louder.

John

They are very loud. Rob Pink has them on his car and my Pantera shakes when it is in the vicinity of his exhaust. Very, very loud

Decibel meters are free apps for smart phones now. My car is about 95 Db just wondering....

Wilkinson removed the internal restriction. I think it was a 1-3/4" internal ring. I also think that was a sound reduction device on the original Ansa design.

When you increase the id of it, you increase the sound level emitted. There is some type of a graph on that somewhere?

Think of it this way, the additional sound is the 50 additional horses trying to get out.

I feel a sound level comparison coming on now in this thread? Anyone else feeling those vibes?

quote:

My car is about 95 Db just wondering....

Exactly where did you take this reading?

John

decibel meter app for my iphone driving around. Car seems to say pretty consistent in the cabin.

Hello
I read this topic, and wonder if somebody would advice me on the "best" exhaust combo (no 180 headers) for my gr4 project please

Holley Dominator, 351cu, single carb, 4v heads, magnum 294 comp cams
Best regards
Philippe

If you are attempting to assemble an authentic appearing 1972 Group 4 engine, duplicating those built by Bud Moore Engineering, the GTS headers would be the correct ones.

Hall Pantera, Paramount California

If you want the best performing Pantera headers money can buy contact Pat Mical:

Performance Automotive Technology, Tyngsboro Massachusetts

He doesn't mention, Pat Michal, the headers on his web page, but as far as I know he is the only one who has bothered to build a real collector into the GTS headers?

A 3" collector is necessary to make the headers scavenge. That is one of the benefits of fabricated tube headers.


It would be interesting to add a thread to this on what the decibel level readings are that everyone is getting from their systems, EVEN STOCK!

With the availability of the free sound level apps for smart phones, this is a piece of cake.

At this point just saying, stock, a little louder, etc, can be put into numbers so that EVERYONE has a reference to what can and can not be done sound wise?



I'm getting flack from people who are just looking at the exhausts and telling me they are illegal. They haven't even heard them run.

I don't know where that is coming from since I keep looking high and low and can't find one violation in the statutes.

It might simply be that people don't believe this is a production '73 model year car? They want to know where the catalytic converters and the air pump is?

Anyone out there that has experienced being stopped for "roadside examination" on their cars like the CHiPs still do occasionally in CA?

Thank you
Here are my headers ... They are supposed to be GTS ones ?

Hello
anybody to identify my exhaust please ?
regards
Philippe

Well, they are not stock. They look rougher than my GTS headers. Mine may have been repops. They did not have the tooling marks in the tubes like yours do.

They maybe original factory gts headers by the original vendor? They are definitely tri-y's.

As such they are giving away about 30hp on the top end but provide more low end torque off of idle.

They work best on a basically stock engine. They do not work well on a high performance/race engine.

quote:

Anyone out there that has experienced being stopped for "roadside examination" on their cars like the CHiPs still do occasionally in CA?

Doug, I haven't had any problems with CHP in So.Cal. I drive both my 67 mustangs and pantera on weekends mostly. No issues what so ever with the CHP. The BAR does set up a road side random smog inspection complete with dyno but I have read that its voluntary.

I suspect it will get more and more difficult to drive these cars as the years pass.

This is a copy of the MidengineMike build with a 284 hyd roller cam... I also cut the collector off the headers and replaced it w/an opened up ball collector...

https://www.youtube.com/watch?v=nic5OQCFCus

Does anyone know the actual primary tube diameter of the Wilkinson headers and also the diameter of the exhaust pipes? I have read and heard conflicting measurements. Thanks.

Primaries are 2" OD

tail pipes are about 2-3/8" OD.

Thanks George.

George is correct on the primaries. The exhaust pipes are actually 60mm (2.362"); tail pipes (tips) are 70mm (2.75").

Wilkinson also sold (as a set) stainless steel headers and mufflers. These were also available in mild steel. Primaries are 45mm (1.77"); exhaust pipes are 60mm (2.362"); tail pipes (tips) are 3".

I don't know what he is currently selling.

John

Thanks John. How is the quality of his stainless exhaust?

I visited Steve recently. He is out of stock on his exhaust system presently.

quote:

How is the quality of his stainless exhaust?

It seems to be ok. As with any polished SS exhaust, it will require occasional cleaning.

As a reminder, always make sure that the flange is FLAT before bolting the headers to the cyl head.

John

It is good to know that the Wilkinson exhaust is decent, however the system is sold as a whole, and I don't want the headers.

I have tentative plans to make a custom stepped stainless header with a 3" collector and a 2.75" choke. Stainless Headers built a set for one of my other cars and did a great job.

you got it, nice

As stainless exhaust goes, it requires alote of maintenance, but if the intention is to build 180,s, stainless radiates alote of heat!

quote:

Originally posted by "72 GTS:
Hello
anybody to identify my exhaust please ?
regards
Philippe

C-302 B heads

I don't recognize the application of those headers? What are they for?

quote:

Originally posted by pantera chris:

quote:

Originally posted by "72 GTS:
Hello
anybody to identify my exhaust please ?
regards
Philippe

C-302 B heads

Maybe, but I don't think so? I have a set of those here.

This is what the mounting flange looks like.

These are Halls that bolt to the stock Pantera exhausts.

The important thing is the shape. Those generally show the obstructions they need to clear.

I hope this helps on the sound question.

quote:

Originally posted by PanteraDoug:

quote:

Originally posted by pantera chris:

quote:

Originally posted by "72 GTS:
Hello
anybody to identify my exhaust please ?
regards
Philippe

C-302 B heads

Maybe, but I don't think so? I have a set of those here.

This is what the mounting flange looks like.

you are right Doug, but I was basing my conclusion on the mounting holes, it is obvious they leaked. I think they may have started as 4V.

quote:

Originally posted by PanteraDoug:
I don't recognize the application of those headers? What are they for?

Those are F355 headers. They replicated the factory headers in 321 s/s. They then modified the factory clamshell that covers these headers since the primary pipes that they used were slightly bigger than OEM.

quote:

Originally posted by pantera chris:

quote:

Originally posted by PanteraDoug:

quote:

Originally posted by pantera chris:

quote:

Originally posted by "72 GTS:
Hello
anybody to identify my exhaust please ?
regards
Philippe

C-302 B heads

Maybe, but I don't think so? I have a set of those here.

This is what the mounting flange looks like.

you are right Doug, but I was basing my conclusion on the mounting holes, it is obvious they leaked. I think they may have started as 4V.

VERY LITTLE bolts up to those heads. Headers would not without adapeter plates, but why bother? In a Pantera, just get the right headers.

Stainless headers are absolutely beautiful new but I like the ceramic coated steel better.

Just take some Windex and wipe them down. If you want to go crazy, buff them with Mothers wheel polish.

The ceramic maybe will get a little dull if you are running lean and super heating them but even then they wind up looking like "mill polish" stainless.

Hi,
i`m planning to wrap my Hall headers (as in PanteraDoug`s post) with basalt fibre to reduce heat in my engine bay.
Especcially the pipe coming very close to the oil filter concerns me a bit.
Does anyone have experience, how much and what material to use?
Best regards,
Philipp

Do you ever drive the car in the rain?

I have heard the heat-wraps can cbsirb water and cause corrosion...

Only if you drive only a few tens or hundreds of meters and the headers don't heat enough for the water to evaporate

quote:

Originally posted by Rocky:
Do you ever drive the car in the rain?

I have heard the heat-wraps can cbsirb water and cause corrosion...

...I Second this. I have been told by more than one Experienced Source, that 'Wrapping' Header Tubes....Yes, Keeps Some Heat from concentrating in the Engine Bay, 'It' also keeps the Header, itself, from 'Cooling', Therefore Accelerating Disintegration of the Steel. Plus, It Looks Like Crap, In My Opinion. So Go For It!

If Your worried about the Oil Filter taking Heat, change to a Remote Filter System. Also think about the Fuel System winding around/near the Header.

On my race car exhaust I only used wrap where there were no other options. Likely the exhaust temps are higher with a race engine but it was very evident that the wrapped parts deteriorated much quicker than the exposed pipe. I built “air blades” or simple shields where possible which actually worked better anyway. For street use coated helps a lot.

Mike

Recommend getting the headers Jet Hot (or similar) coated. Makes a huge difference in temperatures. My headers are cool enough to touch within 5 minutes of turning the car off.

I have read through this whole thread and kudos to you guys who fab up your own 180 degree headers.

I think I am going to stick with the under the car approach. The improved sound would be the major advantage for me on the 180 degree route, but I really like how easy it is to get to the engine, plugs, etc. I don't think I want to give that up for sound.

Actually getting to the plugs isn't that difficult with 180s. The only issue is you have to jack the car up to slide underneath.