or semi open or just plain closed chamber heads. that are on my 70 454.what compression will it have with flattops.verses 2465 speed pros. thanks

flat tops around the 8.5 to 9.0 maybe smidge more it really depends on the deck and gaskets used........flat top with two brow relief and small dish circle in the piston with a .20 deck and .020 head gasket and 100 cc chambers it around the 9.28 to 1 mark.......

what are the specs on the other pistons.......dome size?

they are closed heads.......most consider (or maybe its just me) 96 to 106 are closed......

106 - 113 semi open.........

anything over that open chambered......

Jsut for the record, my 290's CC'd at 104 cc after .008 resurface, 2.19 int valve install, hardened exh seats(w/ 1.72 valve) and a little unshrounding around the valves (and I mean very little).