I'm looking to re-work the exhaust my '92 road race car (stock 305 TPI). I've got two goals with the re-work:

1. Replace the broken stock, single cat Y-pipe.
2. Build a Y-pipe that will flow better than the stock single cat y-pipe that's on there now. The goal is to get the car closer to the 230 rwhp / 300 tq limit. Its best dyno was 219 / 289.
3. Reduce weight by swapping the 3" single in / single out 30 or 40 series Flowmaster muffler that's mounted in the rear with a lighter unit that's located in front of the axle.

Class rules dictate that I keep the stock exhaust manifolds, but I can run anything I want downstream of them. Sound is not that much of an issue as the only track that has enough sound restrictions is Laguna Seca, and that's only run once a year. I can make provisions for that if nessisary.

What I'm considering doing is putting a small, lightweight muffler where the cat was, and then running a 3" pipe back and provided I have ground clearance either exiting just before the RR wheel, or just going over the axe and straight out under the right side of the bumper.

I'm looking at either a 12" long oval 3" in / out Borla XR-1, a 1 chamber 3" in / out Flowmaster or a Moroso 3" in / out spiral flow muffler. The car currently has a 30 or 40 series 2 - 3 chamber Flowmaster on it.

Does anyone have any thoughts about or experience with these mufflers? Are there any other lighteweight mufflers I should be looking at?

BTW - I'm also open to suggestions on location of the muffler and design of the exhaust system, so if anyone has any suggestions please speak up

Thanks!

- Nick
http://para.noid.org/92z