I really learned something from this thread. All this time (40+years) I thought the distributor cup assembly was just to grease the shaft bushing and I've turned it tighter a quarter turn every time I changed the oil, filling it up once in a while with long fiber wheel bearing grease. I had no idea it stablized the shaft. Maybe I better check it all out as I'm running the truck about 500 miles a week loaded over our mountains. I can't afford a breakdown just now. I have a spare distributor to check out too.
