a buddy of mine just hit 370whp @ 14psi on his 4.3L full size chevy THE THING IS ******* SICK, pulled my other friends mach1 (302whp 310ft.lbs) bye about 2.5 car lengths from a dig i cant wait his is a custom FMturbo, do you think my STS @ the same PSI could hit the same number or close.

 

with the same C/I, IAT, exhaust backpressure, etc it should be pretty close.

 

has your friend done anything for internals? what is the compression ratio on those stock 4.3s?

 

9.2:1, totally stock internals, just has new valve springs, and revs out to 5400rpms. its a t3/t4 60-trim garrett but other than that i havent a clue as to the rating on his turbo. guys have made as much as 400whp on totally stock bottom end fine with a p1sc so i assume turbo as the same. he just running a 3" dp to a borla 3" turbo muffler dumped. pretty quite until it hits boost.

 

what I would like to know is what fuel system mods he has done. The stock 4.3 fuel system doesnt support much.