Cylinder head milling
With quench heads you want 0.035" to 0.040" piston to head clearance to achieve the mixture motion intended. With that close gap the flame front does not move into the gap until the piston moves down from TDC.
With an open chamber head you do not have the quench generated mixture motion to aid the speed of combustion. I can not guesstimate on what clearance would become a hinderance to flame propegation. Any larger volume that does not burn quickly and is subjected to the heating and pressure rise is at risk of detonation. With that in mind I would be more inclined to zero deck the block with pistons that have the correct Compression Height and a dome of no more than 0.200". A higher dome also inhibits flame travel which can contribute to detonation. A short dome of 0.100" may give the desired compression while still having good flame travel.
When designing an engine build consider the desired end result and look for pistons and camshaft that will be compatible with the head design and flow specs.
