Hemi Grind Camshaft

The original one was P3690214, 284 advertised duration .471 intake, .474 exhaust on 108.

In 1983 it was replaced by P4286631, 280 duration .474 lift, straight pattern on 110. The idea was to improve both idle quality and power.

In 1989, P4286631 was replaced by P4452993 which has identical specs, and the 993 is still a good part number today.