Ati Performance Harmonic Balancer - Supercharged Super Damper - 7.074 in OD - SFI 18.1 - Steel - Black Oxide - Internal Balance - Big Block Chevy - Each-918871E--Notes: 6 Bolt Hub The hub has 1) 3/16 Keyway and 1) 1/4 Keyway State Restrictions- Canada Restriction-NO -Emission Warnings--NO Truck Freight ---NO