Skip to main content

579 replies

Pantera # 5357 - Rocky's 1973 L model

rockyrockyMember
Dyno Day Completed -

Lots of great tuning, and 20 good pulls on my "new" motor.

It ran great, sounded good, was happy and well behaved. We found some issues that would befuddled me if I had tried to solve them in the car (low fuel pump pressure, and a terribly stiff vacuum secondary diaphragm that felt OK, but was causing the secondaries to open late / erratically).

In fact, we spent the whole morning working these little challenges. Once we got past these issues, we were able to tune the engine to optimization.

What we seemed to find was that ultimate power is currently limited by my exhaust - primarily in my header collectors.

I was able to run / tune with all the critical systems of my own car (flywheel, distributor, air cleaner, ignition, coil, headers and muffler).

It was a long day, but a fun time, and a great learning experience for me.

Rocky
Last edited by rocky
panteradougpanteradougMember
quote:
Originally posted by Rocky:
Well - everyone has to make trades on the configuration of their motors for various reasons (cost, fitment, etc.)

I am convinced (as is my builder) that Doug is right, and the limiting factor in this build is at the end of those headers.

Does Hall sell Fiat parts?


Most of the disappointment is from the exhaust BUT I've played with that intake and I can tell you that just a Torker is night and day over it.

The Holley Strip Dominator is documented 25hp over the Torker. Not by me. By an ancient magazine article and possibly confirmed by one of Dan Jones dyno pulls? I'd have to re-review those?

What you have in that manifold is a pretty thing but it is the best to use with an automatic transmission, not a manual.

I was running a Holley 4779 with a leaned out idle circuit so it wouldn't smart you eyes at idle.


I think that it is the entire header itself that is the issue. This is ancient technology that the Pantera chassis on "under" headers restricts.

You need a 2" primary tube header, about 36" long primary tubes, and a 3-1/2" collector about 6" long to maximize exhaust contributions.

Simply put, that's a no can do in a Pantera. Not on UNDER the car headers.



Most headers are going to have two long and two short tubes on each side. That's more a function of what the builder can get into the assembly and to get it to fit to the chassis more then desire. Even the 180's are not going to have all equal length tubes to them.

In an early Mustang it is possible to get equal length primaries, or very close to it.

So sure, there is usually a compromise somewhere. I do remember Dan Jones saying that the Blue Thunder intake had 4 ports that flowed well and 4 that didn't and it needed to be reworked. That was proven on McLain's flow bench. Makes sense to me from my own results with it.

To be 100% truthful, I ran the Shelby lettered version of it. It is said that the Blue Thunder is a "continuation" but I can't verify that. I gave up on it 25 years ago. It's a good thing it's pretty, 'cause it sure isn't very smart?



How much power there is to find in the exhaust probably varies from set up to set up, but your induction flow has got to compliment the exhaust. Your's doesn't.

It is probably safe to say that with the right headers, there should be 75 to 100hp hiding and ready to be unleashed.

With a 1-3/4" x 24" long primaries, right there that's a killer BUT just simply changing the collector on THOSE headers is probably an honest 25 to 30 hp gain. I'd do that as a minimum.

The problem is, it doesn't fit well through the rear suspension.

Look at the headers from Pantera Pro-formance. They reduced the collector to 3" for clearance to get it through the suspension BUT it's a real collector and ANYTHING helps. The primaries on their GTS headers are also 2".



If I were you, I'd start borrowing sets of headers to try on the dyno before you settle on a combination. Maybe even a set of 180's to compare the power differences with? Check out Dan Jones dyno's. I know he was working on headers but don't remember how far he got with those tests?

The headers that you have are certainly alterable collector wise. The issue is going to be if it will clear when you put them on the car.



Why don't you let someone else do the hard work and either buy in or copy what they did?

Also a full 2-1/2" exhaust won't hurt either. Those only loose a couple of horse power at the very top rpm's to a full open 3" exhaust. That's not bad at all but 2-1/4 is restrictive.

None of this is your fault. From the very beginning the original Pantera exhaust was a bad compromise.

When 350hp was a lot of power for the street, that wasn't a problem. Things change.

http://www.precisionproformance.com/


And just to add on another thread here, I wouldn't be surprised at all that 1.8 rockers show a noticeable increase AND that is a cheap trick as well.

Just be sure that the valve springs can handle that extra lift.


Of course this experimenting would be simpler if the dyno was yours and you could mess with the set up under no pressure to get off of the machine?

So what do you need 500hp for anyway?

That's your dyno in your garage right? Big Grin
Last edited by panteradoug
rockyrockyMember
You guys are funny. Irritating too.

It's very easy to spend somebody else's money.

All the choices in my car are a trade between performance, budget, amount of labor to install and getting the parts to fit in the vehicle while retaining a relatively stock engine bay, that can have a tub in it.

Nevertheless, I am willing to have a more scientific discussion on the current state of my engine.

Yes, I had all the spark plug wires installed.

The carb is now a Holley List 4609, modified for 4 corner idle, and has quite a bit of work done to it. 735 CFM.

Holley 4609

Yes, it is currently set up with a vacuum secondary carb. Previously, I was running a Braswell double pumper racing carb, with mechanical secondaries, and no choke or choke horn. This was swapped because:

  • It wasn't mine
  • It was a PIA to start every time with no choke

    Testing on the dyno showed a constant vacuum across the venturis through the RPM range (3000 - 6000). The engine is not running out of carburetor.

    Testing on the dyno indicates that once the engine was making peak horsepower, changes to jet sizing, and changes to timing had very minor effects on the power, yet fuel consumption could change relatively significantly.

    My builder is also convinced that the restriction is in the collector in the header. This was determined by testing without the tailpipes (enlarged) and the ANSAs.

    You can see the modifications already performed to my exhaust in this thread, and the link below also implies the "standard" Hall Headers are not optimal. Sorry about the missing photos...


    ANSA MPS-1 Modificaiton

    Joules Comments on Collectors


    Anyway - The motor is off the dyno. I have a lot of work to do to get the motor back in the car.

    I am happy with what I have done.

    I will hold off on installing the headers till near the end of the project. I am sure that by that time, this group will have "crowdsourced" me the ~2500 it will take to buy the correct Pat M. or Pantera Pro-Formance headers and exhaust that will unlock my missing 30 HP. PM me for PayPal instructions.

    Likely, I will have enough donations to get a set of both. If you guys do that for me, I promise to post up a review of each configuration. This will allow you all to criticize other aspects of my build.

    Rocky
    • Last edited by rocky
    rockyrockyMember

    IMG_6466_[Small)Shakedown cruise today - getting ready for a trip to Monterey.

    Riding with the Cobras... unfortunately, the number of Panteras in Tucson is dwindling!

    Should be a good trip up Mount Lemmon - I'll post up pictures.

    I am very happy with my new motor from SRE Motorsports.... there are two more SRE Engines in the Cobras here....

    Rocky

    Here's the pictures - link to the "Events Photos" Forum...

    Shakedown Cruise with the Cobras.

    Attachments

    Hide
    Images (1)
    • IMG_6466_(Small)
    Last edited by rocky
    R rene4406Member
    quote:
    Originally posted by PanteraDoug:


    Look at the headers from Pantera Pro-formance. They reduced the collector to 3" for clearance to get it through the suspension BUT it's a real collector and ANYTHING helps. The primaries on their GTS headers are also 2".


    I dig up this subject.

    You say the collector of Proformance headers is 3" but on their site they write 2 1/2" ??????

    Beyond this question, do you think these headers are the best for a street engine of about 450 HP?
    panteradougpanteradougMember
    quote:
    Originally posted by René #4406:
    quote:
    Originally posted by PanteraDoug:


    Look at the headers from Pantera Pro-formance. They reduced the collector to 3" for clearance to get it through the suspension BUT it's a real collector and ANYTHING helps. The primaries on their GTS headers are also 2".


    I dig up this subject.

    You say the collector of Proformance headers is 3" but on their site they write 2 1/2" ??????

    Beyond this question, do you think these headers are the best for a street engine of about 450 HP?


    I would go with what the website says, but I would think that the exhaust pipe is 2-1/2" and the collector 3"?

    I wouldn't know which headers are the best. I've got Hall's 180's.

    Pat Michal has dyno numbers on his. As I recall, they were impressive numbers.

    From what I can tell, they are very high quality and very well engineered.
    rockyrockyMember

    06-17-2014_[6)_(Medium)06-17-2014_[6)_(Medium)Hi Rene -

    My headers started life as "Hall Big Bore" headers. They have 1 7/8" primary tubing, but we cut out the (crappy) "merge", installed a much improved stainless band clamp between the headers and tailpipes, and then upgraded the stock tailpipes to 2 1/2" all the way back to the stock Ansa cans.

    Even with these mods, I might suggest there may be better header / muffler solutions that could provide increased performance.

    (Rumor has it that / I have heard anecdotally) the Hall headers are a boat design. The best thing about them is the clearance of the engine bay and suspension with no, or minimal mods to the stock tailpipes and mufflers.

    There are no "collectors" per say - only the 4 tubes coming together at the same spot. I am convinced there is more horsepower in my engine wanting to get out, stifled by my exhaust configuration....

    That being said - "better is the enemy of good enough" - I'm not in the market at this time for a new exhaust (in both Euros, or time).

    Here's a link to the exhaust portion of my thread...

    5357 Exhaust Upgrade


    Here's a picture of the "merge" and the flange from the Hall Setup... that HAD to go...

    Attachments

    Hide
    Images (1)
    • 06-17-2014_(6)_(Medium)
    Last edited by rocky
    R rene4406Member
    Hi Rocky

    I watched and read a little (it's hard for me to read in English) the 43 pages of your topic, you did a very great job.

    I also think to modify/improve the exhaust of mine with a pipe exhaust as big as possible according to the suspensions and I'll perhaps make the mufflers myself but I am not able to manufacture the headers and wish to buy the "best" possible without going up to 180 ° which modify too much the original aspect and prevent to use the rear trunk.
    rockyrockyMember
    Rene -

    Thank you for the compliments. I appreciate it.

    My headers were chosen for fit and compatibility over ultimate performance. We all make trade-offs.

    I, too, would be interested in learning the BEST "through the suspension" header, tailpipe, and muffler combination.

    Who knows, I might be tempted to upgrade!

    Regards -

    Rocky
    rockyrockyMember

    Got a small new project completed today - seat belt holder-uppers!  My wife will greatly appreciate this one - it always took about 5 minutes of fumbling for passengers to fasten their seat belts.

    Anyway - I started by ordering 2 Ford "Buckle Sleeve - Black 12"" from LMC Truck for $13.90 plus $8.75 shipping.  These are Part No. 48-2334-BL. Then I set them on my bench for 3 months.  This is an important part of the process.

    Finally I got motivated, and trimmed the tops to clear the upper half of the buckle assembly, and shortened the tubes, and cut a notch so that the installation would force the belt to stand up straight between my Corvette C-4 seats and the center console. 

    I am very happy with how it worked out.  Labor was easy, and the plastic holders were very reasonable.IMG_9956 [Large)IMG_9957 [Large)IMG_9958 [Large)IMG_9959 [Large)IMG_9961 [Large)IMG_9962 [Large)IMG_9963 [Large)IMG_9964 [Large)

    Rocky

    PS>  The last picture is added as a special bonus for two of my friends.  They will recognize the connection!  Thanks to you both for your hospitality!

     

     

     

    Attachments

    Show
    Images (8)
    • IMG_9956 (Large): LMC Sleeve - As Delivered
    • IMG_9957 (Large): Buckle Trimming
    • IMG_9958 (Large): Finished Upper Sleeve
    • IMG_9959 (Large): Mount Configuration
    • IMG_9961 (Large): Pass. Side Installation
    • IMG_9962 (Large): The "Big Cat"
    • IMG_9963 (Large): Installation Complete
    • IMG_9964 (Large): Bonus Picture
    rockyrockyMember

    No - I kept the bottom loop, which is attached (from the factory) to a steel (powdercoated, or painted) bracket. 

    At the bottom end (where the belt bolts to the floorpan), I had to cut the sleeve (slightly) so the painted bracket can sit flat on the floor, and the seat belt webbing is rotated so the belt is oriented straight up.  The rest of the plastic bracket rests on the carpet, and forces the seat belt to stand up vertically.

    It will be obvious once you get your hands on one and look at it in the car.

    Pictures 4 & 5 (counting from the top) try and illustrate it.

    Rocky

    Thanks for the compliments.

     

     

    rockyrockyMember

    Group 4 Tail Lights getting prepped for install.

    I am using the Pantera Electronics light modules, so the surface of the buckets doesn't have to be "ultra reflective".  The insides were much shinier when I got them, but they got a light "soda blast" to provide a clean surface for the finish. 

    The Jon Haas (P-E) setup runs the wires through each of the bucket light sockets, so in this case, they are not required.  I expect to do some work to seal off the insides  as I run the wires through the back of the buckets.  Probably use heat shrink, or some other technique. 

    I am pretty excited about this upgrade.  It should be a pretty easy swap.  I have some matching connectors to the stock harness coming from Jon, so once I get the buckets wired up, and the light assemblies installed in the buckets, the swap from the US lights, to the Group 4 configuration should be a snap.

    Fingers crossed!

    Rocky

     

    IMG_0837 [Large)IMG_0838 [Large)IMG_0839 [Large)IMG_0840 [Large)

     

     

     

    Attachments

    Show
    Images (4)
    • IMG_0837 (Large)
    • IMG_0838 (Large)
    • IMG_0839 (Large)
    • IMG_0840 (Large)
    Last edited by rocky
    PreviousNext

    Add Reply

    Views: 33,625
    Post

    Membership Required

    We're sorry. You must be signed in to continue. Sign In or Register
    ×
    Are you sure you want to remove from your Block List?
    ×
    Loading...
    ×
    When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
    Note: if you proceed, you will no longer be following .
    ×
    Link copied to your clipboard.
    ×