The flat spot was on the distributor housing, not the cam. If the distributor got clocked wrong and the wires in the cap got walked around a couple of towers to compensate, oil to the passenger's side lifter oil gallery got shut off. Later distributors had a full circle groove instead of a flat.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!