These 3-5/8" bore forged pistons are designed with a small recessed dome for intermediate compression piston for engines with S&S Super Stock® cylinder heads. These pistons can be used to increase the compression of S&S Sidewinder® kits for Harley-Davidson® Evolution® engines and in S&S engines with Super Stock cylinder heads. These are also used as a intermediate compression piston in 3-13/16", 4-5/16", and 5" stroke engines for Harley-Davidson® Sportster® models equipped with S&S Super Stock® cylinder heads. These pistons are clearanced for 5" stroke big twin engines with small (8-1/4") diameter flywheels, and are made from high strength low silicon forging for racing applications. +.030" oversize.