How To Figure Compression Ratio

I would bet that most aluminum heads will have a smaller chamber/more compression than any but a radically shaved open chamber iron head
If it runs nice now on 93, I'd guess your somewhere around 9.5. Most aluminum heads will boost that, I would guess a half point at least. You could go to a calculator and plug in head chamber volume, 88/89 cc's for 906s 452s etc, 82 for a shaved iron head, and 75 for a typical aluminum head, and see what happens......