Swap pistons for quench?

Checked my heads and they need some additional work. I just measured the cc’s in one chamber so far, but depth of the chamber in one head varies from 30 to 40 using straight edge and feeler gauges. I planned to clean them up from 30 years of sitting so I can even that out to with a clean up cut and grinding some from the one hole that’s 30. The other head is about 60 in all four. Pending how the cc looks like I will need to mill around 20 more on that side. Oldmanmopar says I need more compression. What can I run with say 35 quench in iron heads on 94 octane.