Even for this top-dog version of the 502, we're only making a few changes to the basic engine as delivered. We selected a Crane Street Roller (SR) camshaft (foreground) with 262/270 degrees of duration at 0.050- and 0.636-inch lift. The cam has an iron distributor gear so you can run a standard gear on your distributor. The ramps on the cam lobes are designed to give the highest rate of lift without damaging the lifters on the street. Steeper ramps mean more power, but they also place a higher load on the lifters, thus reducing lifter life.