ok, me and my roommate want to switch heads.
He has a 99 firehawk, and i have a 2000 sierra with the 5.3. I want his heads due to a t76 wanting more and more boost, and he wants the higher compression from my 5.3 heads. My question is, how much power increase will the 5.3 heads give him on his firehawk? is it worth the time to do it? his car is all stock, minus the free mods. He is going to port the heads and get a cam at the same time.

Thanks for the help in advance guys,

Dan

 

he won't gain anything since the 5.3's have a 1.84 intake valve, he would hafta change out the valve to a 2.00 to make power... u on the other hand, would gain quite a bit, although ur compression won't go down that much, maybe .3 i guess...

 

too many variables

depends on the port job/head work he gets

 

ok lets say, stock 5.3 heads on a ls1, no port