The solution is easy, trying to diagnose the problem without tearing the engine down wasn't. I would have scratched my head for a lot longer time if I hadn't found this discussion. I thought I was keeping it simple by measuring dist shaft end-play, gear height,
oil supply etc.
On the Speed Pro cam that I first had in the motor, they didn't even turn the rear face of the gear. The cast surface extends all the way to the top of the gear teeth. If you run your finger along the leading knife edge of the gear, (culprit zone) not only is it sharp but it has an abrasive quality due to the surface texture making the machined surface that interfaces it, irregular.
Tom