I know, i know, but it's the thinkin' that always gets me in the end. Last night I retrieved the original 596 heads (I mistakenly said 587s before, I was wrong) from this motor. Measuring one of them, I've got 64, 65, 65.5, and 67cc, end to end. Looks like the head's not flat. But I think it'll give me the CR I'm looking for. I know I've seen a post about how many thousands to mill off for a cc, but I haven't been able to find it again. I'd like to get them cut flat, and having a # to give the machinist would be nice. Any idea what it might be?