These cast pistons are used in S&S Sidewinder® kits for knucklehead, panhead, and shovelhead engines, as well as in complete S&S engines for 1966-' 84 Harley-Davidson® shovelhead models. These pistons are used for 4-1/4� and 4-1/2� stroke engines with stock diameter (8-1/2�) flywheels, and for 4-3/4� stroke engines with 8-1/4� diameter flywheels. 3-5/8" bore, +.050" oversize.
