1970 Machine turn key off, take out...engine runs

I had that with my 73 javelin. Found my ignition switch was worn and grease hardened, thus sticking the ignition switch into run even with the key out.

I ended up rebuilding mine at the time, as I was in college and limited budget, books were just purchased.

What you can do temporarily... is squirt a wee bit of liquid wrench. Not a lot, into the switch where the rod pushes the actuator. With no power connected from the battery, use the key to go in the start position and off, back and fourth 10 or so times. You should feel the action become more free and return of the tension as well. Once done, with key off, connect the battery and check to see if the instruments are on. If not go a head and start, let it idle a wee bit and turn off. The switch should allow disengagement and power off the engine. If trouble becomes persistant, replace the ignition switch.

Are you running MSD ignition? I had that problem. There's a solution for it that requires a Mopar ballast resistor.

-Steve-