S&S Cycle SS-106-5242 570GE Easy Start Gear Drive Camshaft Kit for H-D Big Twins 1999-06 BT & 2006 DynaS&S . 570 inch lift cams are designed for 88 to 96 inch engines with compression ratios between 9: 1 and 10: 1. This 570GE Gear Drive Easy Start cam is designed to greatly improve valve timing accuracy by eliminating timing chain lash and Easy Start Cams allow stock starter to start any engine. For 1999 2004, these cam are not bolt in and need special springs. These cams are bolt in for 2005 2006 and can use stock springs. * Note, This Kit does not