It could be bad bushings in your distributor, my 48 Willys would run great then all of a sudden just die (usually in the worst places) and not offer to start again. With you distributor cap off grasp the rotor and try to wiggle the shaft back and forth. If the bushings are worn you can actually see the points move. Bushings are hard to find now a days it seems, but I found them at Tractor Supply Co. other farm stores may have them. It's really not too difficult to rebuild a distributor if you have too. I hope you find out what is causing it soon, hope this may help.
