I am kinda new at this engine rebuilding thing and I would like to know if the heads on a 305 and a 350 are the same? Interchangable? would it produce higher compression? And would it be possible to create a mean 305?(i'd like to keep the stock motor).
Thanks....

 

Welcome aboard, Jeff.

Stock 305 and 350 heads are not the same, they are interchangeable to a point. Some aftermarket or newer 350 heads are too big for a 305. If the combustion chambers are different sizes, you will see a change in compression. I believe I have seen a supercharged 305 around here somewhere running 9s, so yeah you can make a mean 305.

 

 

You say stock 350 and 305 heads are not the same, yet interchangable. I have a stock 305. What will adding a 350's head of same make and model do to my engine's performance??

LO3 305 TBI all stock currently

------------------
un4givin89



1989 Camaro Ralley Sport, 305 TBI 5 Liter v8

Project List:
Crate 383 Engine
Flowmaster Exhaust
New Tires
Windows tinted
Interior swapped for two tone colors
Lowering Springs
Sound System

www.mikekey.net

 

I you use a set of 350 heads on a 305 your performance will probably suffer. The main difference between 305 and 350 heads are the combustion chamber size, and port and valve sizes. I think most 305 heads 55-58cc where as most 350 heads are 64-76cc. If you used the 350 heads your compression ratio goes in the toliet. Also the valves and ports are pretty small on 305 heads in comparison with 350 heads. You could buy a set of aftermarket heads at say 64cc and have them milled to the 305's chamber volume. the stock and most aftermarket heads will physically change and work between the two engines but it's best to get the correct heads for your application

 

sounds interesting. I don't plan on ever doing this, but I was curious. Love to leanr something new! Thats why I love these forums, always learn something everday when I check them.