Lift is the part of the cam lobe above the base circle. Measure the entire lobe of the cam...then determine the base circle...the differance between the two numbers is the lift. On a flathead motor..this is your total lift...minus whatever clearance you have. On a ohv motor..the rocker arms have an effect also. According to the ratio of the rocker arm..the lift can be considerably different. To find the total lift there...it must be measured installed..at the valve.