After driving a while your truck won't start won't say nothing all the head lights and radio work but when you turn the key nothing After sitting a while it starts?

Have starter load tested. it's your solinoid Older Chevy's are known for this problem. it is because the starter and selonoid are so close to the exhaust that they get hot. this causes more resistence in the selonoid so it just needs to cool down. Try some heat shielding to prevent the problem.

If the starter/solenoid does not fix the issue...you should also check the ignition module and the cap/rotor. Had the exact same issue. The module will over heat when you have a bad rotor or cap. When it's cold it will start right up, but if you ran the car to the store and tried to restart, it wouldn't start for at least 10 minutes. Then it would start fine. Turned out the rotor was bad, which was causing excessive voltage requirements which overheated the ignition module. Changed them, and, voila, problem gone.