1985dodge Ram 318 motor

Does the truck lose spark when it stopped working, or has this been an intermittent problem?
The thing about electrical diagnosis is the way a part can work fine for a week, not work one day but works the next and so on until it fails completely.

I am not sure if your year truck has an ignition ballast resistor. It looks like a long coil on a piece of ceramic. Test it for resistance as they can fail and look okay. There is also an ignition box on the firewall that has, a rubber boot with a center, "Pole" of rubber to grab and help pull the connector off. The boot has an upside down pentagon shape and I believe 5 or so wires coming out of it. It is the Control Unit and can cause a no-run issue and fail intermittently.
Make sure your distributor bearing is good.
Let me know what you find and I will watch for your reply and get back ASAP.