i have an 84 Z28 with a 283 in it. its pretty powerful for a 283, 041 heads, 9.5:1 compression, cam with 278/288 adv duration, 204/214 duration at .050, and .422/.444 lift, performer intake and 600cfm carb and headers. its nothing special but its a LOT faster than a stock 305. the problem i have is that i had a y-pipe made for the headers i have. the guy mad it 2" coming off of the collectors into 2" for another 6" after the "y" or "T". the pipe is tiny, its about the size of 1, 1 3/4" primary tube that is on another car i have because it has a bend in it also. i put a fuel pressure guage in the hole for the 02 sensor and reved it to 6000 in park. the guage would go up to about 7-10 psi which is a lot for backpressure. how much psi do you think i would get at WOT while driving it? and about how much do you think it is hurting me?

also, could it be hurting gas milage much? thx

 

what's the rest of the exhaust like.long tubes 3in cat back,no cat?

 

it has a 3" catback, no cat, with a flowmaster muffler.

i've been thinking of just getting hedman headers and the y-pipe that fits with them but i've heard of the y-pipe hitting the oil pan. i have an aftermarket oil pan though so i don't know if that would be any better.

 

oh yeah, the headers that are on it now are flowtech shortys with 1.5" primaries.

 

Does it look smaller than my custom Y that I had made for my Dynomax shorties?

 

you can always get a slp-y-pipe

 

it looks like its about the same size pipe but mine comes together to make a T. if you can just fit your fingers around the pipe to touch then its about the same size.

the SLP pipe is for stock manifolds isn't it?

 

stock manifolds or shorties.they work on both.

 

I have the headmann headers and Y pipe and they work fine they don`t hit the oil pan