Hays steel flywheels are manufactured from certified billet material that will not break up under the stress of high RPM and severe punishment of racing. This 25-pound flywheel fits SBC, BBC, except for 400 and 454 motors, with 2 piece rear main seal. It has a 168 tooth ring gear. The flywheel is drilled with one pattern for 10, 10.5 and 10.95 inch Borg & Beck pressure plates. Internal engine balance and S.F.I. 1.1 certified.