Wiseco K1770 3.527" Bore 8.5:1 Compression Ratio Domed Forged Piston Kit Fits: All Harley-Davidson Shovelhead engines 1978-1984 80 cubic inch (1340 cubic capacity) kit includes 8.5:1 compression ratio domed pistons, rings, circlips, chrome piston pins 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 Compared to cast pistons, forgings are tougher and more durable, and will stand up to the abuse that high performance motorsport applications require