This 5" stroke 8-1/4" diameter flywheel assembly replaces the original flywheels in S&S^® 103" SH103 engines for 1970-'84 HD^® big twins. Balanced to S&S^® 3-5/8" bore pistons. Flywheels are CNC machined from heat-treated, closed die, steel forgings, and are stronger than cast iron or late style steel flywheels. Dynamically balanced and fully assembled with premium quaility S&S^® mainshafts and heavy duty 7.440" connecting rods.