Start any engine regardless of displacement or compression ratio with a stock starter. Save your starter and battery; tested for 10,000 starts without running battery down. Allow for easy start by initially reducing crank compression, but once the engine starts and rpm increases, the compression release lobe is centrifugally retracted and the engine runs normally, with full compression, and without any loss in performance. Available in chain drive and gear drive versions. All chain-drive cams include installation kit. All gear-drive cams include 4-gear set and installation kit. Gear-drive cams also available with inner gears only; intended for cam replacement for motors that have already been converted to an S&S gear-drive system. Made in the u. s. a. NOTE: Installer must check coil bind, valve-to-valve clearance and valve-to-piston clearance. NOTE: Due to the inherent characteristics of gear drives, you may experience more valve train noise. Bolt in cam for 103in. and 106in. Big Bore Twin Cam motors. Use with stock heads (up to 10.2 compression) and low restriction intake and exhaust. Great for lighter bikes with strong power from 3500-6000 rpm.