I have the 2355's in mine. They are heavy like stock pistons. The KB237's used to be quite a bit cheaper and a little lighter. Now I think they cost basically the same. The 2355's are forged and the KB's are hypers. They are both a flat top w/valve relief piston with a ~2.060 compression height. That with a small deck shave will get your pistons dead flush with your deck which is what you want with closed chambered heads + a .040 thick head gasket. If you want to get a little spendy you can get comparable pistons, forged and much lighter.