The 210 and 195 spec is port volume--not combustion chamber size, however, the issue of chamber cc volume size is an impoetant consideration and as Roger has stated make a very important decision that needs to be made at the beginning of any build that is so important to do with fuel requirements and cam timing choices---Probably the biggest issue you will have is valve clearance notches for a 2.050 or 2.080 valve as not only are the diameters different so are there location in the head which also means offset to gain wall clearance and exhaust valve head clearance which will then require offset rockers(read that as shaft ) and roller lifters with offset pushrods-----$$$$$$$$$$$$$$$$$$$$$$