There are lots of flat tops.. Some will give a true 10.5 C/R & others will only give a 7.8 it depends on the compression height of the piston... When you pull a head bring a piston up to TDC & measure how far the piston is down the bore... To accurately measure this you need a few special tools but you can get a reasonable measurement with straight edge & a feeler gauge...To get a true 10.5 with 88cc heads on a 440 would require the piston comes up to exactly flush with the deck surface of the block and a thin head gasket... Very few do.. A piston .150 "in the hole" and a normal head gasket gets you 7.8... BTW .150 is just a little over 1/8th" or about the thickness of two nickels...