How far in the hole?

.075" was what I had on a '73 318. .060" sounds correct to me.

Also, 64cc seems to me to be on the small side. Most castings hit 67-72cc, depending on the valves that are in it.

I checked my closed heart chamber 302s with open faced valves and they hit 62cc. They advertise 59cc with closed valves, I'm guessing they come in somewhere between 60 and 61.

If you are looking for more squeeze, get a machinist straight edge, check the block and heads with a feeler gauge against it and if it's nice, go with a pair of 1121G Mr.Gasket .028" compressed and hit the bolts with 95ft lbs.

That will get you closer to your figures by .030"-.032" ish, if your pistons are, in fact, down around .060"

I'd still be skeptical of the CC. Easy to check, though, with a piece of plexi, white grease, alcohol and water mix with some food coloring and a 100 mL / cc syringe.