S&S CYCLE CAM 509 GD 99-06 330-0017Bolt in cams for 88 CID engines with stock compression ratios, Increases valve timing accuracy by eliminating timing chain lash and loosely fit stock chain drive, Reverses the rear cam's direction of rotation, providing additional operating clearance between cam lobes; resulting in higher cam lifts that are possible with the gear kit, Material must be removed from inner surface of the stock gear cover to install, S&S recommends that adjustable pushrod