ATI Performance Products 917278 Harmonic Damper: Automotive. Buy ATI Performance Products 917278 Harmonic Damper: Crankshafts - ✓ FREE DELIVERY possible on eligible purchases. Harmonic Balancer - Serpentine Super Damper - 6.780 in OD - SFI 18.1 - AC Pulley - Aluminum / Steel - Black - Internal Balance - GM LS-Series - Each Notes: Y-Body 6-groove w/A/C pulley, 10% underdrive. 。 Established just outside of Baltimore, Maryland specializes in Automatic Transmissions and their Components for the Racing Markets. Within the ATI Product line you will find Harmonic Balancers and their Components, Crankshaft Hubs, Dipsticks, Timing Pointers, Fasteners, Fluids, Tailhousings, Automatic Transmission and more. 。 。 。