305 heads on a 350?

[big_blue_chevy2006]

ok i cant find this thread in here but im sure its here somewhere, but can i put a set of 305 heads on my 91 350? super chevy show is here in a month and if i can find a nice set of 305 heads at the swap meet i want to get them AS LONG AS they will work, i will plan on doing a valve job and buyin a port and polish kit from mr gasket and doing a small port and polish job, but before i buy them, will it work, AND what all do i need to make this work?

[broughy84]

They should work. I'm putting a set on the 283 I'm Building, and that set came off a 350. A SBC head is and SBC head pretty much, unless it's a 2.02 or a 400sbc.

[Riche]

"buyin a port and polish kit from mr gasket and doing a small port and polish job"
Get to grinding on the exhaust ports!!!!

[big_blue_chevy2006]

wut i meant by small was that the kit even says its not good enough for like a race job but it will really make it nice, itll take a few hours but i think itll be worth it.

[Riche]

The exhaust ports are a downfall to those heads. I built a motor like that a few years back. Do as much as you can to open them up... I am sure there are some guys out there who really know how to port a set of heads, they would probably say that you are in over your head, but I say grind away... Just remember to spend more time on the exhaust!!!

[big_blue_chevy2006]

alright thanks i just cant wait for the show and ill get a nice set of heads i hope and ill see what happens

[big_blue_chevy2006]

i ahve another question tho, wut exactly does 305 heads do on a 350, or if i can find another set of heads at a swap meet for cheap wut should i look for?

[jveik]

i heard that the 305 heads are a little higher compression when put on a 350, but i would bet that the 350 heads flow a lot better than 305 heads would. i would stick to the bigger heads unless ofcourse you are doing it for compression's sake.

by the way, are the 305 heads any different than 350 ones? maybe they are the same cc's and stuff and are interchangeable? i dont know much about the differences btwn engines

[Riche]

They basically raise the comp. ratio. I had a little help when I built mine from someone who knew what they were doing. The engine ran well but don't think about using low octane gas. I had to retard the crap out of my timing to get it to run without knocking its a$$ off. It would probably be in your best interests to try to find a different head. Back when I did that to my old engine, that was one of the big things to do. But you don't hear much about it anymore... Ask yourself why??? I think jveik covered it. You can find high compression heads out there that flow allot better than 305 heads if you want them. I am not trying to stop you though, the only way to learn is from experience!!!
As far as what to look for... that is a hard question to answer, b/c it depends on what you want.
May I ask what is wrong with your heads? why not take them off and grind away at them, get some valve compound, re-seat the vales, and put them back on and see what happens???

[profox02]

sdfd

[profox02]

my '91 chevy pu had a 305 in it then i swapped it out with a 350 crate with an rv cam and used my 305 heads ....the compression is higher so it will knock if you dont use higher octane gas.

[big_blue_chevy2006]

well my old heads of my 90 engine(stock motor) were cracked so i put in a 91 motor, well come to find out the valve guides are bad and in 3000 miles i burned 2 quarts of oil, the valve stem seals and brand new.

[airdale94]

305 heads have 50cc combustion chambers as opposed to 85cc on late model 350's. So needless to say they will up your combustion ratio drastically.