Jeep j20 won't cut off when running?

[claypotL]

I have a 1985 jeep j20 pickup with a factory amc 360 and th400. The other day i turned off the ignition and pulled the key out but the truck didn't cut off. I went home, pulled the coil wire and the truck shut off. I then put the coil wire back on and tried to start it but when i did the starter didnt disengage after it started, I am wondering what part is likely to be the culprit. It has the factory Motorcraft sourced ignition