− Decrease quantity for Harmonic Balancers, Super Damper, Serpentine, Internal Balance, 6.78 in. O.D., 6 Groove, SFI 18.1, w/6 Groove A/C Pulley, Aluminum, Black, Ford, Each Quantity + Increase quantity for Harmonic Balancers, Super Damper, Serpentine, Internal Balance, 6.78 in. O.D., 6 Groove, SFI 18.1, w/6 Groove A/C Pulley, Aluminum, Black, Ford, Each Add to cart