Jacques, I would go ahead and get a rebuild. Sounds like your shaft is worn. You can easily destroy your engine if the timing shifts at speed. Had that happen with a 478 V6 once, picked up a piece of block about six inches in diameter. the mechanic had shimmed the worn shaft while he waited for a new distributor to arrive. I blew the engine the next day.... frown


Fred
52 3600
69 C-10