Ok, so this is for a floor shift column. It can be a formerly column shifted car, but the outer shifting tube has to be removed for this to work.
Mopar originally equipped these cars with a lame plastic lower "bushing" for the steering shaft. It doesn't really control the shaft all that well, and it costs like $80 to replace. You know, this dumb thing..
Enter the ER16 flange bearing. It has a 1" inner diameter, and an outer diameter of 52mm. Turns out the column jacket has in inner diameter of ~52mm. Just a smidge less actually. So, you can search ER16, SER205-16, etc. I got mine here http://www.ebay.com/itm/1-Insert-Bearing-ER16-ER-16-SER205-16-NEW-/280300800190?pt=LH_DefaultDomain_0&hash=item41433ac8be
Now, a little work. This is for a '74 that started out as a column shift, so it has the little flange that's riveted to the column jacket. I removed it, and cleaned it up with a dremel. If you have the earlier version (pictured above on my '71 GT with factory floor shift), don't fret, its the same inner diameter.
At this point, the bearing should slide in about half way.
Now, for the '74 this was easy, I just put it in a press and pressed the bearing home, all the way up to the removable clip it comes with. Seemed like a good place. For an earlier column without the removable flange, you'll still have to find a way to press the bearing the rest of the way, or tap it in with a hammer etc. Keep in mind it really doesn't have to be a press fit, so you can remove a little more material if need be.
I reattached the lower flange with metal screws, and tightened the allen keys. The astute will notice the shaft coming out of the column in the picture is a 1"DD and not a stock 1" round, I did some more modifications. But don't worry, the ER16 will fit the standard steering shaft as well, its also 1". You'll probably have to clean it up with a wire wheel or dremel to get the bearing on, it slid onto some of the steering shafts I have, and required a little more motivation on others.
No play, no falling out of the column, and it cost $9 shipped to my door.