well when you send the jug and head to ken to get ported, ask him to look at the cylinder walls and measure the jug. Ask him for his opinion on wear. If the cylinder walls arent scored or damaged badly you can get away with just some rings, but if they are scored then you will have to have him bore the jug and you will need the next size up piston and rings. And if your reasembleing, remember to replace the base and head gaskets. OEM is what i would use but ive heard that cometic gaskets are holding up pretty good.