based on what you gave for specs, i get 10.42cr now, and it would take 14cc's off the heads for 12:1.

you cut Indy heads are roughly .006 per CC, so for a 14cc reduction, you're looking at cutting them .084.
better check the V/P clearance before cutting them that much.

cut the intake side .012 for every .010 off the deck.
so, if you cut the decks .084, cut the intake side .100.