As soon as the engine dies, pull the coil wire out of the distributor cap, and hold it about 1/4" from a good ground lile the cylinder head. Have someone crank the engine, and see if a spark jumps to the head. If not, see if the points are opening and closing normally. The coil, and possibly the condenser can have temperature issues. A very narrow point gap can also close up as things heat up, but that one's a really rare problem.
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!