I did the same thing on one of my cars but it was price prohibitive to buy a new column. I took the shifter arm out, removed the collar and ground the shifter boss flush with the collar. Next, I inserted a temporary backing using styrofoam and proceeded to fill the hole with bondo. Fiberglass would have worked well also. I sanded the collar to the exact curve and paint finished it. I didn't even remove the column to do this because it was black. That was four years ago and I would challenge any one to spot the conversion.