Since the Twin Cam engines became available, their potential for more performance has already become an established fact. Andrews has designed and tested new cam grinds which show that more power is within reach. The Twin Cam has a very broad torque curve compared to earlier engines. All of the Andrews performance cams are intended for use with the stock hydraulic lifters and Andrews EZ-Install push rods in anodized aluminum or chrome-moly steel. EZ-Install push rods do not require removal of tanks or rocker boxes for installation. Andrews also offers a heat-treated 34 teeth rear cam drive sprocket for late Twin Cam models. Early Twin Cam models have the gear fitted to the cam with a key, where later models have a splined camshaft and gear. These sprockets are made from heat-treated alloy steel with a wider than stock press fit for greater stability. Gears are highly recommended for use in your stock engine but must be used with any Andrews cams. Gears are not included with the cams, they must be ordered separately. Andrews cams are available for all Twin Cam models. "Silent Chain" version fits 1999-2006 Touring, 2000-2006 Softail and 1999-2005 Dyna. Early 1999 models may require the seperate purchase of ZPN 700835 splined cam sprocket. "Roller Chain" version fits 2007-2016 Touring, 2009-2016 Trike, 2007-2017 Softail and 2006-2017 Dyna.