compression or flow?

If you take the quench down it will kill power. BTDT.

I know it’s a PITA but you are better off decking whatever you need to get to .040 piston to head clearance from the block.

That area is around .100ish from the factory, maybe a bit more. That means you‘ll have taken at least .100 off the heads and head gasket sealing will become problematic.
I bought the heads used and didnt know they had previously been cut. Didnt realize the open part was that deep stock. These heads cc to 75 cc!