My thoughts, since the 351 shaft does not fit into the 5.0 distributor hole it was riding on the end and slipping causing the distributor to stop/start turning and shut the car off.
My question is if it don't fit the distributor and fits the oil pump is the oil pump wrong?
Just thinking out loud.
The shaft fit into the oil pump,but the distributor end was different. However,the car had oil pressure. You figure if it was skipping it wouldn't, and the car didn't have a miss either. Weird.