These gear drive timing sets are specifically designedfor LS engines used in racing,street, marine and extreme applications. They provide themost accurate valve timing possible by eliminating chain flutter and backlash. They bolt on without modification, maintaining the stock oil pumpand timing cover for all LS-based engines except dry sump models. Dry sump engines (LS7, LS9, etc.) require an external oil pump. These are the world’s only gear drivesfor LS engines and are based on the award-winning COMP CamsLS Sprint Car Gear Drive. LS Gear Drive Timing Sets are designed for three-bolt cams and work with all 24x and 58x LS engines.