Distributor seems to jump out of timing?

Moab-MoparKid said
I have a friend who also has a 71 dodge dart swinger with a 360. He's been having trouble getting it timed. I told him to bring it over and I'll give it my best shot. When we drove to my shop I could tell the timing was way off the car was hard to start but when it did it was fine....until you gave it some gas and gained rpm's. The car would fall flat on its face. When we got it to the shop we put a light on it and it was off(can't remember the degree) and no matter which way we would move the distributor the car would die. Then I noticed it seems to be jumping out of the distributor gear? The end of the distributor shaft seems to have marks of it slipping? does he have a wrong length distributor? or would it be the gear inside the motor?

Put the timing lite on again and watch the strobing. Just rev it up until it starts misbehaving and watch. If the timing jumps backward and forwards or starts dropping sparks, I could be that the polarity is reversed on the pick up. The correct pick-up has one orange wire on it, and I forget the other color but it doesn't matter, as it's the orange one that matters. The plug-ins are wired for correct polarity with the orange-wired pick-up.
But if the strobing is consistent and not dropping sparks, then I would sooner look at the reluctor or rotor phasing. But first disconnect the VA and try again.