360 Aftermarket Heads on 318

krazykuda said

I've measured a 318 head at 66 cc, so the aftermarket heads may not need any milling to keep the same compression as the stock 318 head...

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That's what I was thinking! so even at 66 cc's the 63 would actually raise compression. I did some quick math on the standard 318 cylinder volume vs the quoted 63 cc combustion chamber and the math works out to around 10.3:1...ish