msd 6

I agree that the coil would be the first suspect. When an msd goes its usually sudden and doesnt work again. A coil typically fails slowly and symptoms start when it gets hot. Its not uncommon for a coil to fail but then work fine again once it cools off.

have changed coils , first thing I thot about , also many other changes , runs like a 505 should till I hit a bump , then dies ...but will restart , suspect a wire grounding some where when I hit that bump...