.570″ valve lift. CD = Chain Drive camshafts, complete kit with gasket and bearings. Bolt-in 88″ to 103″ with 9:1 to 10:1 CR. 3200-5700 RPM overall power increase. Easy Start Cams make starting easier by reducing the build-up of cranking pressure in the cylinders during starting. This is done by lifting the exhaust valve slightly of its seat, with a spring loaded compression release lobe inside the camshaft. After starting the compression release lobe is retracted by centrifugal force. The only difference is during starting since you will now be able to electric start your Big Inch engine effortless, without the use of big batteries and/or starter motors. A stock starter and battery is enough. When the engine is running the camshafts function as regular cams, without any loss in power, torque or anything else. Note: Only 551, 570, 583, 585, HP103 and MR103 series cams are bolt-in, all others may / will require clearancing and require high lift valve springs. Note: Not compatible with kickstart models. Note: Only camshafts made before Jan. 2010 will require adjustable pushrods. Note: Below 900 RPM you may hear a clicking sound. Adjust idle speed to 1000-1100 RPM.