I searched but didn't what I was looking for. I just bought a 94 gt that has the stock h pipe which has been gutted. The car has all the bolt-ons including GT40 "Y" aluminum heads, 1.6 roller rockers, larger MAF and throttle body, an E 303 cam, UD pulleys and more. The exhaust consists of BBK shorty headers and flowmaster 2.5" two chamber cat back along with the mentioned gutted stock h pipe. My question is in terms of horsepower how bad is this hurting my gains or should I say how much will I gain by switching to some form of O/R pipe?

 

well gutted cats dont get as much gains as a o/r. plus you wer still running 2 1/4 inch pipe. i would def get a o/r midpipe next since you have all those other mods. it will sound better also

 

yeah hard tellin, i would say significantly.

as a guess, possibly 20+ hp.

 

20+ hp? from not having a o/r mid pipe? Dang...is that because of his midpipe or because of his piping size too?