ATI Performance Harmonic Balancer 918911; Super Damper 6.325 in. External Balance for Ford 289, 302, 351W

The patented ATI Super Damper is the only damper designed exclusively for high performance engines. Eliminates torsional crankshaft vibrations Exceeds SFI 18.1 specs Laser engraved 360 degree timing marks Black zinc chromate finished Inner and outer shells are available in aluminum or steel contain the steel inertia weight. The inertia weight has six (2-ring design) or eight (3-ring design) computer machined grooves to retain the proper durometer O-rings (dyno tested for each application).