1968 318 questions

My 69 318 is basically the same (9.2:1). I removed the original heads and checked the CCs, they were 69ccs. I had a set of 302 heads and checked the ccs, they were 69 ccs. I swapped them out and it gave me no great benefit except for the closed chamber. So to answer your question.....the 302s should work just fine with no loss in compression. You can easily check the CCs with a large syringe (irrigation syringe), won't cost you more than a few bucks?? CCs = ml
PS- the valve you use can also increase your compression!
PS, PS - 302 heads have hardened valve seats....A big plus if you plan to use our newer gas formulations!!!

Bard Piston Syringe with Resealable Bag 60cc

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