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. The 30 pound flywheel fits the 454 Chevy with 2 piece rear main seal and has 168 tooth ring gear. The flywheel is drilled for 10.5 in Borg & Beck or diaphragm and 11 in Borg & Beck, diaphragm or long style pressure plates. S.F.I. 1.1 certified. External engine balance. Other weights and applications available.