I have an 87 camaro with 305 computerize carb I want to put the heads, intake, and carb on a 76 350 out of a van. I would like to know how big of a came to use in it.

 

Thought I'd give you a little bump to the top, as well as put you in a better place for good answers.

 

The heads from a '76 350 are going to be a bad choice. The earlier "smogger" heads had very small valves and poor flow volumes, and intakes to match. Beyond that, the chamber volume of the 350 heads (probably 76cc) is going to drop your compression ratio to extremely low-performance levels, like 7.5:1 or less. Lawn mower engines go that low, but not much else.

Depending on the heads you have on your 305, you may already have better flows, and likely already have much better compression. And there are a lot better choices for replacements.