Engine cranks, but won't start

79 early electronic ignition, check out rotor cap. Somewhere if I remember right there is a porcelain ceramic white rectangular block, can't think of the Technical name, but I know that when they go bad nothing will start. I'm not sure where Ford put theirs if it is not on the firewall, check the wheel well covers(under the hood) and I think I have seen them next to the radiator, I'm thinking it is called ignition transistor.

Also look around the plug wires and see if you may have accidentally unplugged important ignition wire including a ground wire.

Are u still getting fuel to the carb? Bad fuel pump perhaps? Does ur truck have dual tanks? If so it will be on the rear of the front tank mounted to the cross member