Quote:
Originally Posted by 1funride
I agree its time for a new exhaust any recommendations?
Its a 408 now with a mild HFT cam, cam will be changing to a roller in either the 408 or possibly a stroker. Would like an exhaust that can support the 408 and even up to a 467 if possible. A bolt in fit is always good.
Currently have doug's headers, plan on keeping those, and a flowmaster american thunder 2 chamber transverse cross flow muffler. The engine specs are 408ci, edelbrock D port 72cc, port matched to PP Crosswinds intake, water cross over cut to maintain port alignment, Ultradydne 274/282 226/233 .515/.515 w/1.65 H25/H18 Lobes LSA 112 ICL 107, MSD 6A, MSD Ready to Run, Fitech EFI, timing is 12 initial with 21 coming in at 1250 and full in at 2850.
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I don't believe your exhaust is holding you back. I ran that exact same exhaust system on my dyno run in my 70 formula that I mentioned above with it's stock 400.
Matter of fact, when racing the car, I started with the stock Gardener exhaust system. Upgrading to the Flowmaster 2 1/2" transverse system with H-pipe, and no other changes, didn't touch the engine, the car picked up a solid 5 tenths ET and went from 98-99 mph to over 102 mph consistently.
That's a solid 30 HP gain using the slide rule, with just the exhaust change to the Flowmaster transverse. This same car again, I later swapped over to the Pypes Transverse system, with X-pipe, still 2 1/2" system, because I couldn't help but wonder if the Flowmaster was hurting HP from all the stories you read. The car gained absolutely nothing. So at my power level with this car, it didn't care if it had the Flowmaster transverse or the Pypes transverse system on it.
It might come into play at bigger HP levels if you're pushing 500+ at the crank, but at our power levels, the muffler design and the X-pipe did nothing.