14 This is the 4-5/8-inch stroke SE Pro Flywheel Assembly. The flywheel assembly is made of high-strength forgings and then precision-machined to shape and balanced to ensure smooth operation. The high-strength material is much stronger than the OE flywheel assembly, which allows the flywheel to be pressed-fit to much tighter tolerances. Basically, the OE flywheel material couldn’t handle the press fit load the SE Pro Flywheel Assembly is subjected to. The crank pin has a thin coating on it, the coating is designed to help with the integrity when the crank pin is pressed into the flywheel assembly. Once pressed together, a Hess Mae machine checks for proper run out.