Most people use Chvey van columns because they have the gear indicator on the column and no key. I used a standard car column and adapted a gear selector -- glued a van (or older model non-tilt) selector quadrant to my column and a pointer on the moving end. It works. As for the key -- I couldn't use the switch because there isn't enough room under the dash for the switch on the column. So I removed all that and put a chrome metal plug over the switch hole. Looks better than an extra key switch anyway. The only modifications I had to do was to the foot where it connects to the floor. I cut the one off the column with a cut-off wheel. Early GMs usually had a clamp-on foot, so you should be okay. My Rambler had a flange on the column perpendicular to the column then a bolt on foot that fit to the floor. I split the bolt on foot so I could get it on the "new" column, then made two right angle brackets to bolt to the foot where the original column bolted on. A big pipe clamp holds the column to the brackets. I also had to make a new bracket to hold th column to the dash, but that was easy as bending a 2" wide strip of 1/8" steel and drilling to fit.
As already mentioned, you'll have to cut your steering shaft and weld on an end for a rag joint. I think I have a better suggestion though. Get a steering shaft (short one) from a newer car. You'll notice they use a "double D" shaft on the collapsible part, with the hollow part toward the column. Pull the lower solid part out (might take a hammer). Cut you original shaft off then grind two flats on it so it will slide into the upper part of the newer shaft. Don't worry about the "sping", just make sure you have at least 6" of overlap in the shaft. Now you have a collapsible column as well! At least it will collapse some (instead of pushing the wheel into your chest) in a catastrophic wreck, and if it pushes at much of an angle would come out.