This innovative tool actually slides down into the lifter bore and rides on top of the camshaft in order to measure lobe lift and base circle runout. Each tool includes two followers: one for solid or hydraulic cams and one for rollers. Two models are available and each is double ended. • Built-in o-ring holds tool firmly in the lifter bore while 1 inch travel dial indicator (not included) reads cam lift to .001 inch • Two models available one for GM (.842 inch dia.) and Ford (.875 inch dia.) and another for Chrysler (.904 inch dia.) and Top Fuel (1.0 inch dia.) lifter bores