I have a 86 305 "F" code pickup truck motor (190 h.p.) that is almost brand new. the other day one of the local guys gave me a set of H.O. 305 heads from an IROC. I ran the casting numbers on the "free" heads and all I found was they were for a 305 '87- >>>, the "free" heads need center bolt covers and probably some machine work to be usable. my question is: will these heads work on my '86 block, and will they be worth the effort required to change them (h.p. wise)??

 

I tried to find the casting numbers on my current heads and could not see them without removing the cover, but , theyre standard heads for the above mentioned motor.

was the center bolts the only change chevy made to the heads from 1986 to 1987 ??

will my intake and carb work with these heads ??

 

well, first of all the F code motor is a 305 TPI and was never put in a truck so I'm unsure what's up there but either way; the 87 heads will bolt on an 86 fine. the differences would be the centerbolt valvecovers and the center 2 intake bolts on each head are a different angle. You can elongate the holes in the intake slightly to make them match. Just make sure you don't grind into the lifter valley when you elongate them or you'll have an oil leak there.

 

that confused me also, I ordered a LG4 from chevy but received the "F" code motor instead, the reciept had this on it "P86F305"
when I called chevy and asked them about it they decoded it as:
P=pickup, 86=1986,F="f" code motor,305=disp.