If your 64cc heads are vortec and not dbl hump it is to your favor, and if your cam is a longer duration than stock that will also help you.
I would also bet that unless you've decked the block to zero, and calculated the gasket thickness, valve relief recess volume, crevice volume, and cc'd the combustion chambers, to have actual proof of the 10-1 estimated compression ratio - that it isn't actually up quite that high.
If your quench distance is .041" or less that is great, if it is greater you're much more likely to have detonation.
I'm assuming you have iron 64cc heads - if they're aluminum you're very likely fine.