The whole distributor housing moves with vacuum, not the breaker plate inside the distributor like most others. Check to see if the wire from the distributor to the coil has any broken strands, especially at the connectors. If it's got breaks inside the insulation it can cause an intermittent open circuit.

Also shake the distributor cam side to side. If there's a visible change in the point gap you can get rough running and/or an intermittent miss.
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!