Andrews Tw21 Chain Drive Cams For Harley Since its founding in 1972, Andrews Products has been acknowledged as a pioneer in the industry throughout the world of racing. Modern engineering, design, and production techniques are used by Andrews to provide camshafts of the highest caliber for the performance motorcycle market. Features: Only the best alloy steel billets and heat-treating processes are utilized Stock compression ratios and stock pistons Made in the USA Tw21 Cam Specs: Bolt-in cams more torque for all around riding with heavy bikes Peak rpm range of 1700-4800 Intake open/close 10/30 Exhaust open/close 40/08 Intake duration 220/255 Exhaust duration 228/264 Intake lift at Tdc: .134 Exhaust lift at Tdc: .121 Intake lift .498 Exhaust lift .498 Uses stock springs Note : Installer must check coil bind, valve-to-valve clearance and valve-to-piston clearance