Working on a friends 1971 Chev 350 Truck and its having a starting issue, upon turning the ignition the truck turns over and fires no problem. As soon as the operator releases the key the truck shuts off. Does this sound like a power issue to the ignition? The ignition has been changed in an attempt to solve this problem but no luck. I know a small amount about the coil that must maintain power for the truck but not quite enough to troubleshoot it yet. Any ideas would be greatly appreciated! Thanks!

 

Sounds like you have it wired to a wire that only comes on when you start the truck. Find a wire that comes on when the switch is on.