Interesting ideas Jeff. The exit pipes are about 1.45 each for a total area of 3.302 sq. in. combined. The standard ANSA has a 2.405 sq. in. inlet and the GTS is about 3.14.

Mike

My 2 cents...

David Berman has a 540 bhp motor (engine dyno tested) that dropped exactly 20% when installed in his GT5 and measured on a chassis dyno. This is pretty typical of every Pantera I have ever read of that has data for both the chassis dyno & engine dyno (19% to be exact).

David's exhaust system includes the stock GTS/GT5/GT5-S mufflers. I am confident in writing that these mufflers "unmodified" inhibit performance no worse than any muffler for a 550 bhp or less motor.

cowboy from hell

The exhausts I modified in this post now emit 112dB at 3000 RPM. My friend recently had it tested at Goodwood circuit.
A few years ago I had my car tested (with the factory group 3 exhausts) and found it to be exactly the same 112dB. So it would seem having all the holes in the Y piece makes no difference to the volume at all. I certainly wouldn't want it any quieter.

Johnny

Interesting! I kind of thought that with the center inlet pipe with all the holes having 4.06 sq. in. of open area that it would not be muffling anything and might not be restricting the flow very much. For those that do not want to cut open the muffler adding a lot of holes in the front and back baffle could be an easy solution. If loud equates to free flowing exhaust, then I’m making good progress!

Mike