after researching this subject it looks as if 2 1/2" exhaust is too small for my 575 h.p.385 stroker project.i'm a little leary of 3" as that seems a little extreme for a street/strip ride.i'm thinking of compromising and going with 2 3/4".will this be sufficient? i want to keep as much torque as i can and am afraid that 3" might hurt a little.i've already bought 2 1/2" dynomax ultraflows and don't want to neck down from 3".my cams power range starts at 3500 rpm and i have a 4000 rpm stall.suggestions?

Never heard of 2 3/4" exhaust..I suggest you go with 3" lead pipes and 2.5" tailpipes.

I agree with Mr 4 speed, but IMHO would also run a crossover "H" or "X" pipe as well.

If you're running 2 1/2" mufflers they will make more backpressure than if you had 2 1/2" pipes and 3" mufflers. I'd return the mufflers. That's a lot of air/HP for them to flow. JMO

I would use the 2 1/2 system all the way to the back with some type of H-pipe or X pipe and call it a day. it is still 385 CI and IMO you don't need anything any larger than 2 1/2.

HOWEVER, Is this a High RPM Combo? At 575 HP That's 1.5 HP per CI and if it is Normally Aspirated to get that kind of HP smaller exhaust is going to help much on the low end torque anyway.

If you were to go bigger anywhere I would go with Mr. 4 Speeds suggestion, but you will need to use a 3" inlet muffler as was said.

I wouldn't expect any difference in ET or MPH between a 3" to 2 1/2 and a 2 1/2 with a crossover to a 2 1/2 with an under 6500 RPM Combo.

If you really want more than 2-1/2" od you can get a 2-3/4" in a mechanical tube or use 2-1/2" pipe size (= 2-7/8" od). Probably not worth all the effort, but it is available.

Keep in mind he has 2-1/2" ultraflows, which flow about 1000 cfm @20" h20 each. Not very restrictive at all.

thats what i'm hoping will be my ace in the hole..these ultraflows really do let it out.