How much HP would a stock EFI 5.0 SD gain with an off-road H-pipe, No cats, 2 1/2 inch pipes into flowmaster 40 series mufflers. The only mods are a CAI, and timing at 14 degrees and no smog equipment.
RacEoHolic330, Thank you kind sir. Sweet as hell GT you got BTW. Bet she run's like a scalded ape. You only got me in the 1/4 mile by 5 seconds or so...
i'd think maybe 10 at the wheels. I just put an o/r h pipe onto my car, mind you i have stock headers/cb. I don't think mufflers do much performance wise, they do wonders on the sound but i think for the exhaust your best bet to gain hp is through the midpipe (hi-flow cats, or no cats) and some nice headers. All the exhaust companies who manufacture mufflers always claim gains of 10-20 hp just from their mufflers which is bs. I'd think in the range of 10 for the midpipe and some more when you put some headers on.