Pay special attention to the primary wire from the coil to the distributor. It's being flexed constantly as the vacuum advance moves and it can break under the insulation and create a momentary open circuit. As soon as the distributor stops moving the circuit comes back together and you can re-start. I like to use a piece of very flexible test lead wire there.
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!