S&S 510 Cam Kit For Harley Twin Cam Features: Available in chain or gear drive versions The S&S Camshaft Gear Drive Kit increases valve timing accuracy by eliminating timing chain lash and the loosely fit stock cam gears This is accomplished by replacing the stock cam drive sprockets and chain with light press fit S&S gears Because the chain, chain guides, and tensioner are eliminated, there is no longer a possibility for these parts to fail and damage other parts The S&S Camshaft Gear Drive Kit reverses the rear cam's direction of rotation, providing additional operating clearance between cam lobes As a result, higher cam lifts are possible with the gear drive kit Strongest response from 3000 to 5500 RPM Intake open/close 20/38 Exhaust open/close 52/20 Intake duration 238 Exhaust duration 252 Lift .510