It's unusual, not impossible for the distributor housing to lose its ground. A much more likely scenario is for the wire between the housing and the points to develop broken strands, and intermittently break the circuit as the vacuum advance moves. I believe some distributors have that wire, while others move the whole housing. The later-model point-type distributors for the 230/250/292 engines definitely have it, not sure about the 1st. generation stovebolts.
Jerry

Edit: I believe the Pertronix module just generates a signal to the coil, and does not rely on a housing ground, but I don't have enough experience with that system to have any definite knowledge. I do know they have a pretty spotty reputation for reliability, and some folks carry a set of points in case there's a failure out on the road. The GM HEI unit is a lot more reliable, not stock-appearing, though.
Jerry


Last edited by Hotrod Lincoln; 06/20/2010 3:22 PM.
"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!