problems with my 1971 chevy truck

my 1971 chevy truck has a problem and i cant find it can some one give me an idea of the problem ........ the truck runs and starts perfect but then about 15 minuts later it turns off and wont turn it just studders but if i wait i imagine the engine cools down 15 minuts later it turns on for a short wile

i think more information is in order.
what engine do you have?
are there any mods to it?
what about your driveline?
dude there's like a jillion chevy wizards floating around here with answers, but none that can issue said answers without your information on your entire setup and symptom.

well the truck has a 350 angine and has no modifacations it is an automatic 2 wheel drive

1. Fuel pump
2. Ignition coil
3. Ignition points
4. Good tune-up

see?
chevy wizards.