340 build

It will be way cheaper to have a custom thick head gasket made then to have both of your heads machined!!!!
Remember that even thow them piston are above the deck. Once you figure in them big valve reliefs in the piston, you may be closer to flush then you think. As far as cc above deck.
it was something like 6 or 7 cc below deck once you figured in the piston valve reliefs.

With 70cc heads my compression came out to 9.4
63cc head +.060 head gasket(12cc) 7 cc below deck, I come up with 9.70:1 compression.
You will have to cc you piston to know if your valve relieves are the same size as mine were, but i bet it close.