318 complete combo suggestions...

AJ nailed the way I do it. I zero deck the flat top slugs and use a gasket to drop the ratio. If there in the hole to deep, the thinnest head gasket won’t help in what you may end up lacking. Bringing a domed slug flat area to the same zero deck height and you can get a max compression return or, again, drop it down with a gasket.

If you want to build a low compression mill (9.0-1 or less) with a small cam, then the piston placement becomes more importation know exactly where it will sit.

Skip the math lessons. There not needed.