Innovators West Inc Harmonic Crank Damper. Part # 842, 7.25" standard diameter, 8 rib main drive & 4 rib AC with keyway and is SFI 18:1 certified. LS1, LS2, LS3, LS6 Corvette, Pontiac G8 & CTS-V. This damper is off of a C6 Corvette Grand Sport 6.2 liter engine.