I have a 79 F600 that has the keys missing, so I am looking for a ignition switch source.

 

The ignition cylinder w/key did does not come with the ignition switch, but the only way to remove the cylinder w/key from the switch...is with the key.

Therefore, you'll need a new switch and cylinder w/key, NAPA should have both.

Or, you could have a locksmith pic the lock, make a new key. Originally both door cylinders and the ignition switch were keyed alike.

Original Ford part numbers & applications:

D0TZ-11572-A .. Ignition Switch - 6 blade terminals (Motorcraft SW-944) / Obsolete

1970 F100/750 from serial number G90,001 / 1971/72 F100/750 / 1973/76 F100/880 / 1977/79 F600/880.
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C9AZ-11582-A .. Cylinder w/Keys (Motorcraft SW-814) / Obsolete

1967/72 F100/750 / 1973/77 F100/880 / 1978/79 F600/880 / Misc 1969/72 FoMoCo Passenger Cars