When I got my car, the lock cylinder was missing. I bought a new ignition switch and lock cylinder and installed them, however the lock cylinder will pull out freely. I looked in the service manual and saw that there is a lock cylinder hole, but how does this work? Is there supposed to be a pin that slides in there or what? Any help would be appreciated, thank you

With key removed, lock should slide into switch and 'click' into place as mechanism that holds it in the place does its thing. You may need to push into release hole with paper clip or fine punch. To remove you again use heavy duty paper clip or fine punch that you insert into a hole that is at the top of the switch again with key removed, and ease it out.

If you have a both new switch and lock combination you should be good to go.

For further info.

https://board.moparts.org/ubbthreads/ubbthreads.php/topics/617588

1970-71 ignition cylinder has a different release mechanism than the 1972 and up cylinder. The 1972+ style will not lock into a 1970-71 column and 1970-71 will not lock into a 1972+ column.

You've stated you already bought the 72-up cylinder...The easy way out at this point would be to drill a hole{in the column housing} for the locking pin to seat itself...

I purchased one that said it was for a 70-74, which equates to the 72 and up version. That sounds like good advice.....