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Santa brought me a new set of headers from PI Motorsports.  They look awesome.  Big 4 into 1 with 2.5" collector.  They won't fit up to my current Ansa mufflers so I have not installed them yet.

Currently I have a 72 Pre-L Pantera.  Going by pictures in this parts page (from PIM) I have 4th series headers and 3rd series mufflers.  Despite the 2.25" flange on the Ansa mufflers the actual pipe is much smaller, probably under 2" dia.

So here's the question.  Does the GTS+GT5 muffler have a larger inlet pipe and flange than the earlier mufflers (series 1,2,3,4)?  Is it fixed or loose to rotate?  They are stupid expensive.

The only other mufflers I can find are dual glasspacks by Precision Performance and some stainless mufflers by Circuit Werks.  Then there's the option of buying a muffler and having someone custom fab inlet pipes.

Anybody with big bore headers out there?  What are you running for exhaust and how did you mate them up?  Pictures if possible.



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  • Parts Page
  • Circuit Werks SS
  • Percision Performance Dual Glasspacks
Original Post

Fabricating the tailpipes is a pretty tricky effort.  What we did on mine (Wade Musil - ex Pantera owner did my fabrication) was to take the stock mufflers, and fabricate a jig, and then duplicate the routing of the stock Ansas in 2 1/2" tube.

We spent a lot of time "swinging the suspension" to make sure my pipes had clearance...  It helps to take off the wheels, springs/shocks.

The connection we used was one of those "V-Band Clamps".  But to use these you would have to modify your collectors.  You can see the modified collector in the second picture.

This picture gives you the idea. 

If you (or someone else) are doing this - grafting the mufflers on to the tailpipe tubes shouldn't be a big deal.  I don't think there would be any advantage to two of the flange clamps, one is easier to deal with.


07-12-2014 [12) (Medium)07-12-2014 [13) (Medium)

This last picture shows the 2 1/2" tube going into my stock ANSAs.  Of course this was all welded up by the end of the project.


07-12-2014 [10) (Medium)


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jjones posted:

Pantera Performance just wrote me back.  Looks like they are closing.  Guess that removes one more option.

Sorry we do not have this item in stock we are closing down and we will not be getting anymore.

Thank you, Gloria Robles Byars

Mrs Byars was involved with Precision Proformance which I heard was closing, not Pantera Performance which is owned by Dennis Quella.

I have a set of big bore headers and tail pipes, the look out the back never thrilled me. I've looked at them and thought about putting chrome tips on them.  I'm going back to OE exhaust for now.

I've looked at Magnaflow mufflers and they make quite a few different muffler can's that could be tailored to our cars and give great performance. They also offer a large array of custom build parts. You can pretty much build what you want.

I looked at doing a 2.5" & even 3" inlet muffler with dual outlets. They're pretty inexpensive, and if you have any welding skills and tools you can just tack everything in place and remove it and have someone else finish them with pretty welds, or just buy the parts and have a muffler shop put it together.

This is one of the mufflers that would fit with a 2.5" inlet, there is also 2.25" which are a direct fit to the big bore setup if you just wanted to swap the glass packs, then you just add chrome tips to the new Magnaflow muffler.

This is the look I was shooting for.  Maybe someday I will take on this project.



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  • BradDiezPanteraL
Last edited by tomsealbeach
jjones posted:

I'm curious how you mate the OE exhaust with the big bore headers.  An adapter or cobble up the exhaust to use a larger flange?

You could use an adapter that tapers from 2.5” to 2.25” or 2”. Stainless Headers, GP Headers, or Stainless Works either have what you need or would build it for you.  I had GP headers build me a set of headers in 304 S/S with a 3” collector.  They are a modified version of the Hall headers.  I had a 3” exhaust roughed out.  Sent the exhaust to GP Headers to make it that in 304 S/S.  I had them taper the end of the exhaust down to 2.5” to fit Pantera Performance mufflers.  They did a nice job.


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Last edited by jimmym
tomsealbeach posted:

How tight is the 3" tubing as it goes through the suspension and half shaft. I recall looking at doing a 3" back to the mufflers and was told that it would be very difficult to get it through the suspension.  What you had made looks great!

It is tight, but not as bad as I was told either.  I had thought about running cv joints just to gain additional room but didn’t need to.  One shop that had built some exhausts for these cars said that I would have to dent the exhaust for clearance.   When my friend mocked up the modified headers he tried to get the collector centered in relation to the suspension.  I spoke with Dennis Quella from Pantera Performance about what the other shop said about denting the tubes for clearance, he mentioned using oval tubing instead.  Stainless Headers offers oval tubing, and oval tubing transitions.  In the end I didn’t have to but was going to if the round tube didn’t fit.  


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Last edited by jimmym
tomsealbeach posted:

I think going from start to finish with a new set of headers is helpful. I have looked at the oval and that may be a great alternative, but if the 3" round works why bother.  What are your engine details. You must want it to breath. Post photos when it's complete, looks great so far.

It is a 427 Clevor.  Ford Racing big bore Boss block with CHI 225 3V heads on it.  


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