Most stovebolt distributors have a "reverse helix" ground into the shaft that's supposed to move oil toward the bottom of the housing. Try dismantling the distributor and cleaning that groove out, or maybe even deepening it with a ball-shaped carbide cutter in a Dremel tool. Also, be sure the road draft tube isn't clogged and letting pressure build up in the crankcase.
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!