Please be careful with the Hemi piston dome clearance! The clearance on the dome sides need to be bigger, as proposed by OP because the pistons also expand sideways from the heat. And they do expand a lot, for comparison you can see the radial clearance that all pistons have above the top ring, (I just measured a 4" hyper that is .050" smaller above top ring than down skirt). The Hemi dome will expand sideways and up due to heat, so it needs more clearance due to the dome. When I used my old TRW hitop pistons in the late '70's there was a small sticker inside each box that warned about minimum vertical clearance of .060" (I think it was .060 or .065), which was supposed to take care of this expansion as well as rod stretch etc. My