Heres the piston we use on the build up notice the lower ring land for the top ring also we use a pressure relief groove in the piston to help excess pressure not unload the top ring.Notice the top ring its a special ring weve found the it is extremely flat 3 to 4 times flater than most this helps ring seal it also will hold up under boosted heat normal plasma moly rings will not do the job in a boosted application the moly will end up flaking off under the heat and you will lose ring seal.