I used a wisco piston. Get hold of Fredette at his website or call him. He will send you everything you need and nothing you don't. Things like wristpin bearings, gaskets, etc. Also, if you haven't cleaned the KIPS yet, it is a good time to do so. The whole thing will only take 2 or 3 hours. An easy job some evening and the peace of mind that you KNOW it won't blow up now is beyond measure. If your bore looks good, you don't need to do anything to it except maybe emery the edges of the ports. The plating sometimes scores the pistons here. Inspect your old piston and use that as a guide.