compession with after market pistons

no it,s a 77 360, it has been overhauled before i got it it has stander 360 4v heads. i will look for part#. it had set for 6 years and freeze plugs needed change so i went throught it. thanks for replays. i wound like to put a lumpy cam in it cause it,s a four speed with manual brakes so idol is not that inportant. als back from the shop will post a pic. later of piston flat tops looks like. arent the rods all the same just differant piston for compression. als