Wiseco K1602 3.208" Bore 10:1 Compression Ratio Domed Forged Piston Kit Fits: All Harley-Davidson 1000 Iron Sportster engines 1972-1985 61 cubic inch (1000 cubic capacity) kit includes 10:1 compression ratio domed pistons, rings, circlips, chrome piston pins Will not fit XR style head Each Wiseco piston is designed with the proper installed clearance to produce the most power, least wear, and best seal at running temperature, for each application Dedicated forgings are used for superior strength to weight ratio utilizing aerospace alloy with a dome designed for improved flame travel and detailed skirt shape and profiles for stability and smooth operation in the cylinder bore