I have a 68 Chevelle that has something draining the battery. It appears that when checking for the problem that when I whiggle the key the drain on the battery goes away. Just recently the car has continued to run with the key in the off position (still running the old coil and points set up). I checked the assembly manual and different part catalogs but I cannot tell is the key lock/ignition switch in the dash a one piece unit? I would like to order the part before I take the old one out but I am not sure what to order?

Thanks.

The ignition switch and the key cylinder are two seperate pieces so you can keep the same key/lock cylinder if it's ok.

given the situation which do you think it would more likely be - the switch or the lock?

given the situation which do you think it would more likely be - the switch or the lock?
The switch.

thanks I will give that a try

Try diconnecting the switch by taking the connector off of it and see if your drain goes away. You can also use an ohm meter as a continuity tester to check if the switch is passing current when in the off position.