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Here are some pics that will hopefully show how I designed the overlap to keep the RH and LH banks one piece.

Here is the LH header removed.

Here is a shot looking down the collectors. You can see how Cyl's 2 and 3 had to curve down so that 6 and 7 could go over them to the other collector

Pile of spaghetti. I hope I numbered them.. Wink

Originally posted by Husker:
Fascinating. Thanks for taking the time to document your project. Are they all removed as a single unit? Is there a concern for thermal expansion? Quite the undertaking, far, far beyond my abilities. How many times did the block go in and out?

each bank is a single unit like a conventional under car header where the 4 pipes are welded to a flange. They come together and the collectors slip on.

I had them tack welded to the flange so I could remove the individual pipes to solid weld the joints. After I finish that then I will hard weld them to the flanges.

I am not concerned about expansion, the system has plenty of room to move.

The engine never came out of the car. The whole thing was built inside the car. The pipes never came out of the car either until the whole thing was tack welded then they were removed.
I saw it outside for the first time when I bolted it to this engine on the dolly.

The mock up engine is still in the car. The engine on the dolly is another 400 block and heads that I have laying around.

We all have individual talents to contribute on this forum. Thats what makes it so awesome. I love reading other peoples build threads and the ideas they come up with. Currently digging MacMans hood vent thread. Very cool.

Quite a Brain Trust here on the PIBB. Smiler
I tacked the joints on 4 sides so that nothing would move while removing them from the car. I weld up to the tack then grind and sand the tack off and finish weld the joint.

Fast Fact: 48 joints at 6 inches circumference per joint that is 24 feet of welding just in joints!

I use a vise grip quick clamp to hold the odd shaped pipes in position to weld the joints. I have found this to be better that trying to clamp them to fixtures or in a vise. I ground the welding cable to the metal table and the pipe rests on the table.

The pipes are all welded the lengths came out as follows:
1=39 2=39 3=44 4=44 ½
5=38 6=44 7=42 8=41
This is Interesting as I thought that the #1 and #5 pipes were going to be the longest.

I install the pipes in the car to hard tack them to the flanges. I want to point out that all of the fab has taken place with the gaskets and port plates installed as per the instructions. This is done so that everything is spaced properly for welding.

While the pipes are still tacked in the car I start on the header collector tabs. I use a barrel bolt lock from the hardware store and cut it into the individual tabs. The metal is already formed I just need to bend the ends to fit the curve of the tube.

Here are the pieces all made.
The loop end fits a 5/16 bolt perfect. I will be using 5/16x2 stainless button head bolts with metal lock nuts.
I don’t think the nylon lock nuts will hold up to the heat.

I set them on the pipes using the bar from the kit to align them for tacking.

Here are the tabs tacked in place.

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I remove the pipes and mount them in a fixture I made to start work on the tube to flange joint. I start by tacking the tube on a couple of sides.

I made a mandrel that fits the shape of the flange to use to form the ends of the tube to match. I made the mandrel out of some ¼ thick plate that I cut and welded together and shaped

I got this idea from Clayton on the site. Thanks Clayton!
Here is a link to his great 180 build.

I heat the tube and then hit the mandrel with a hammer and that forms most of the shape.

I finish shaping it with a small trim hammer.

Here is a port welded.

I sand the port flat and mount the headers on another engine I have on my work table to weld the outside of the flanges.
Here are some views of the headers that cant be seen while mounted inside the car.
Here is looking at the rear of the pipes showing the overlap.

Here is a top view.

Here is a view from the bottom. Notice how the LH side is closer to the block to clear the fuel tank shield. This was not planned its just how it turned out from fitting the pipes inside the car. You do not notice this from the top.

Here is a view from the bottom of the collectors showing more of the routing.

I start welding the flanges by turning the engine upside-down and welding the bottom.

Then I turn it over and weld the topsides.

I also finish welding the header collector tabs.

I take the headers off of the engine and mount them to the work table and finish off the ports with sanding rolls.
I take the same care that you would take on cylinder heads

Now it is time to finish the collector. Something that I find to be annoying is collector leaks at the flange. I have been able to eliminate them by the following method.
The flanges are 5/16 thick 2 ½ dia and were purchased from Cone engineering.
The thick flanges will not warp or bend. It is important to use thick flanges
Because of the angle my exhaust pipes will be exiting I rotated my flanges slightly.
I mark the flanges at straight up and also find center and mark the collectors.

I will be using fel-pro steel core collector gaskets. I had to file the holes slightly to match the bolt circle of the flanges.

I use 3/16 key stock as a spacer and clamp the flange to the table. I then insert the collector lining up the centerline marks and tack them.

Using the same procedure as the tubes, I weld up to the tack then grind it off and weld the flange solid.

Here is the amount of tube that sticks out from the flange. The gasket is 1/16 thick so there will be 1/8 of tube inside the flange for the muffler pipes. This keeps the exhaust gas pressure from having direct contact with the gasket and significantly extends the life of the gasket.

I also don’t like to hold exhaust pipes to insert bolts so I use a method that makes exhaust hook up very fast and easy.

I weld nuts to the flange and insert a set screw. I use a socket set screw instead of a stud because it has a hex drive on one end and is slightly pointed on the other. The set screw is removable so if the threads get damaged then I insert a new one. I will use nuts and lock washers on this connection.

Here are some pics of the welded and finished pipes back in the car.

Here is a shot looking in through the A/C hole in the back of the body.

More shots from above.

Here is the part where I discuss what I would have done differently if I did it all over again.

I was talking to a friend of mine and he mentioned that Headers by Ed has flanges for the 4V heads and MPG port plates.
Purchasing those would have saved some time.

I might consider buying a pre built merge collector from SPD or Cone. That would also have saved some time.

However,both of these options would add to the cost of the headers.

This project took me a little over two months to complete and cost approx $400 in materials.

I hope people have found the 180 header fabrication portion of my thread informative and helpful.

I get a ton of ideas and inspiration from a lot of places and this is my way of giving back.

I will be building a set of undercar 4-1’s also but I am going to take a break for a while to focus on some other things.
That portion will not be as detailed as this segment was but I hope it will convey some good ideas also.
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I wanted to give big thumbs up to our Pantera racing friends across the pond.
This was one of the many inspirations for my 180 project.

The Dutch Pantera racing team of Team Witch Craft was first featured in the PI Spring 2004 number 118 issue.
They continue to race GR4 looking Panteras across Europe keeping awareness alive.

Their website is:

If you click on the "English" button it only translates the opening page.

The 180 fabrication portion of their web page is in "Opbygning of Pantera Henrik".Then click on "Pantera Udstoedning" and that is their 180 build. Facinating use of flexible tubes and foam for modeling the headers.

I can't speak a word of their language and I don't know if they speak English but if anyone from Denmark knows them shake their hand for me. Smiler

Here are some pics of their work completed.
To me, this is the ultimate evolution of the Pantera.

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Originally posted by tajon:
that is amazing. WOW!

What would be the advantages to using the 180s vs. the undercar or longtube type design?

On a side note, after all this work is 375 HP going to be enough?

Tajon that is a very good question.

The advantages and disadvantages of the 180 design was discussed here. I think you will find it interesting.

I am going to start pretty tame on the engine and work up from there. Initially I think it will be fine to get the rest of the car sorted and get the thing on the road. This will also give me a good chassis dyno baseline to decide if I need to make a header change and or what engine changes I might need to make.

So I guess the answer is, initally yes it will be enough but later on probably not.
Originally posted by tajon:
Brooke, thanks for the link. It was a great read with lots of youtube in between. The 180s sound sweet. Are you going to video your dyno testing with the different headers?

I'm wondering how much louder are the 180s?

I hadn't thought of shooting video but that might be a idea...

I have no idea how much louder or not the 180's will be.
Most people I have talked to just mention that the 180's are a completely different type of sound.
Me Too! Smiler
Seriously though, it will be a year or so until my car spins the dyno rollers.
Lots of work yet to do.

The pipe did come in the other day for the 4-1's
so I can start fabbing those as time permits.
Then its on to further adapting /fitting the 400.

It looks like my other winter projects are going to turn into early spring. Then I should be able to get back to work on the Pantera.
It’s been a long time since I added to my thread, thing always seem to get in the way
of working on the P car. I have been working on this current project since February.

I want to thank Gary Walker and Johnny Woods for their advice and support so far during this segment of the build. applause
I haven't ever built anything like this before and it was nice to have their input.

While working on non P car related projects this winter I had been thinking a lot about the exhaust system to hook to the 180's.
The obvious choice was to hook up some short glass packs and exit out in the side of the engine compartment then out the factory opening in the back of the body. This is what most people have done in my situation where they want to keep the A/C

I just wasn't “feelin” it. Frowner

I did a search on the PIBB for "exhaust" and had over 150 hits! Pantera people care about exhaust for sure.

I love the look of the ANSA's out the back of the car. IMO They work with the styling of the car so well they almost qualify as a styling que.

I decided to route the exhaust differently than was usually done with 180’s. I decided to hook them to some used L model ANSA's that I bought to modify. I have a brand new set of Ansa GTS mufflers but having paid Hall over $800 for them I'm not about to cut them up.

After all the talk of how badly the ANSA's rob power I decided to mod the inside of my used ANSA’s

Then I would take and hook them to my 180's in a way that I can also use them with the 4-1's.

After making the decision to go with the ANSA's I felt better.

Now I was “feelin” it. Big Grin

I also realized a mistake I made with the collectors on the 180's.
Having the collectors attach the way I did with the bolts won't allow them to hook up the same every time. This will make the exhaust system angles subject to changing and requiring a lot of tweaking to get them in the right place again. As any movement in the collector will affect how the exit pipe and muffler sits.

I decided to cut off the existing collector mounts and go to the commonly used collector tabs to be able to mount the collector with better orientation repeatability.

I could have welded stops on the tubes to locate for the bolts but I liked this idea better.

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Then my imagination started working(uh oh..) and I thought if I am changing the inlet pipe, gutting and changing the internal ducting and changing the rusted resonator tips the only thing I am using is the can body.

Hmmm with some simple forms I could make my own can bodies I have a bead roller so I can put ribs in them for strength build internal ducting weld on some tips………(insert snowball getting larger and larger here)

I realize this would add a bunch of work to the project. Maybe it would be better just to use the existing cans to keep it simple.

Since when has any part of my project been kept simple?....... Wink

I believe there are two problems with the typical ANSA system, the Inlet tube diameter and internal baffle architecture and sizing.

I have both a New GTS set and the used US based L model set for comparison.

The U.S based L model system is a joke. It has a 1 3/4 tailpipe entering the can and exiting through two 1 1/2 I.D. resonators.
Probably not a very good flowing system.

The GTS system is a little better. The inlet pipe is actually a odd size and measures 2 3/8 O.D. The resonators are a slightly different design than the L system and have a ID of 1 9/16.

Johnny Woods did some work on a GTS ANSA system.
Here is that thread.Great work here.

I had been PMing Johnny questions about the internal baffling dimensions.

It was interesting, he told me that at the inlet entrance the 2 3/8 tube is actually necked down to 2 inches through the inlet perforated tube.

In his opinion the exhaust exiting through the necked down perforated tube into the small perforated inlet tube of the resonators was the largest restriction. He felt that the area of the two resonators was sufficient to the inlet size but the perforated tubing was by size and routing the restriction in that design

I did some area comparisons out of curiosity.

On the US made ANSA the areas are:
Inlet of 1 3/4 has a square inch area of 2.142
The two 1 1/2 resonators have a combined area of 3.086.
The statement can be made that the mufflers capacity to exit exhaust is greater than the tailpipe can introduce based on in/out areas alone.

GTS Muffler
Inlet of 2 3/8 has a area of 4.070
Necked down to two inches the area is 2.840
The combined resonator outlet has a area of 3.354
The same statement can be made again that the exiting area is greater than the inlet area.

What I am thinking of building is this configuration.
Inlet 2.5 inches area 4.529
Internal V shaped baffling out of two 2 inch od perforated tubes area 5.68
exiting into 2 ¼ inlet 3 inch outlet tips
I feel that the ability of this design to exit is greater than the inlet area

I believe using ANSA resonator tips might be a restriction.

*All areas were calculated as .049 wall tubing.
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Normally I would sit down and list the criteria I wanted the mufflers to meet. Since I have no idea what I am doing I didn't know what to list!
I figured I would make it up as I go.

To get started I wanted the mufflers I was making to be a similar style to the ANSA’s
I made a generic muffler shape and traced it on to a 2X4.

I did this to six of them then cut out the shape on my band saw. I then glued and screwed them together. Because my bandsaw skills aren’t the best I used some body filler to make the shape uniform on the sides and marked a center line.

I cut out four pieces of 18ga cold rolled sheetmetal measuring 12X8 for the top and bottom of the muffler can.
I marked out where I wanted to put the beads for added strength and rolled them with my bead roller. I used a 3/8 roll set and at the tension I was using the beads are ½ inch wide.

I marked the center of the sheet and used a piece of angle iron to clamp the part to the forming block and work table.

I used a plastic hammer and bent down the side until it matched the shape of the form.

Because the metal has spring in it I inserted a steel ruler under it to over bend it so when it sprung back it would be the right shape. I did this to both sides until the shape matched the form.

Then the part was put in my brake and the edge bent up.

Here is a finished part next to a blank sheet that will be the top to the other muffler.

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After making the other top I put the two together to check aligment and overall shape. I was very happy with the result.

The reason those parts were the tops is because I wanted to incorporate a different design feature into the bottoms.
I started by reversing the Isis logo and cutting out a stencil and marking it with a sharpie on what would be the inside of the can.

I rolled the long side beads into the part then installed a 1/8 inch roll set and rolled the Isis emblem. I traced the emblem reversed so I could track it with the small round part of the roll set making it easier to follow the shape. At the tension I was using the bead is ¼ inch wide.

I realize only road kill or very small animals will ever see it on the bottom of the muffler but it was a touch I wanted to add.

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I started building the form for the end caps out of a 1X6 piece of Maple. I cut two pieces and glued them together in the press using Gorilla brand hard wood glue.

I cut out the shape and used a ½ radius bit in the router to make rounded edges. This gives it the same curve as a 1inch diameter circle.

I made a 1/4 inch thick steel plate to act as a retainer for the ends while forming them.

Next was to try a experiment to see if I could flare the holes for the opening and exits in the ends. I bead rolled some circles in a piece of scrap and hole sawed one of them and it fit the tube perfectly and had the effect I wanted.

I cut out the four pieces that were to be the ends and bead rolled the appropriate circles in them.

I cut the reliefs into them and tapped them over with a small hammer. Then I bolted the form plate to the backside.

The top and bottom halves were clamped together and the end tapped in backwards from the top for welding up the relief cuts. This insured it would have a nice fit after welding.

Here are the ends after welding and grinding.

I built a fixture to hold the ends square and then screwed on the tops and bottoms.

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I took them back apart and hole sawed the ends I used a 2 ½ hole saw for the inlet side and a 2 3/8 for the outlet side.

The tips I used are Hooker they are 2 ¼ inlet and 3 inch outlet.

These are the same tips midenginemike used in his muffler thread here.

The tips are slash cut but the angle is very shallow so I measured the original Ansa tip slash cut to see what the difference was.
I liked the steeper angle of the Ansa’s better so I decided to match it.

I marked the tips for the new angle and cut out the metal with a cut off wheel. I put them on a belt sander to clean up the edges. Here is a before and after comparison.

Here are all the parts lined up ready to begin building the fixture to weld the tips to the ends.

The GTS Ansa mufflers have the tips exiting at an angle. I like the look of this so I decided to match the angle with my tips.

I screwed the bottom on to the ends and mounted them into the same fixture I used to square them and welded the jig to locate the tips.

The reason I used a 2 3/8 hole saw on the tip ends of the can is because of the angle the tips.It could not be angled up with a smaller hole. I taped the tips to prevent weld spatter from getting on the chrome and welded them to the ends.

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Next was to build the internal piping. I bought a 4ft long piece of stainless 2 inch dia perforated tube. It is a magnetic alloy so it can be welded conventionally using ER70S2 rod or wire.

I purchased it from here:

I constructed a V similar to what Johnny Woods did in his thread.

In order to get a good fit from the perforated tubing to the 2 ½ inch inlet pipe and get a good surface to weld to the end cap I welded a ½ wide piece of tubing to the end. This piece was a 3 inch piece that I cut down to fit snugly to the outside of 2 ½ tube.

For the tip ends I made a simple offset reducer cone to go from the 2 ¼ tip to the 2 inch perf tube. The offset was for the angle the tube enters the tip.

Here is a view from the end of the tip showing the fit at the entrance

Here are the pieces all done and ready to be welded in. After welding into the muffler can I will wrap them in fiberglass muffler packing.

Last edited by pittcrew
Originally posted by Rapid:
I have to tell you something, wait a minute while I wipe the drool off! Awesome! Seeing all of this makes me feel so useless. I truely admire your talent! Great job and thanks for sharing with us!

Rapid, you are hardly useless, your car has been an inspiration to me and I am sure others in many many ways.
Thank you for your kind comments.
Originally posted by comp2:
I am not sure if I helped you but I have always been inspired by you welding and fabrication!

Gary you have been a big help.
Its nice to bounce ideas off of someone who is like minded.
I was definately in the dark on this one having never built a muffler in my life.
It was nice to get yours and Johnny's input.
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