Check the wire from the coil to the side of the distributor. If you can wiggle it and make the engine cut out or stumble, chances are the same thing is happening when the vacuum advance moves the distributor housing. Broken strands of wire under the insulation or at one of the terminal ends can cause an intermittent open circuit. It's like turning the ignition switch on and off quickly.
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!