Does this sound like the ignition switch?

Clip voltmeter to coil +. Turn key on to "run" and read. Should read 6-10V or so. Wiggle switch to see how stable it is

Now pull and ground coil wire so it won't fire. Crank engine using the key and watch meter. Voltage should be at least 10.5 or "about the same as battery" when cranking

If those readings are OK, the path through switch, through bulkhead, and to coil are OK