Rebuilding stock 3 spd column shift

[Speedster 229]

I'm currently installing a 700r-4 in my 1970 1/2 ton which now has a turbo 350 trans. I've read and appreciate all the info on this conversion. I want to retain the stock column shift but it is really sloppy. I understand how to tighten up the lower end linkage etc. and get it to get all 4 gears but the slack apears to be in the upper end possibly under the collar. Can this be rebuilt or tightened up? Can anyone give me some help on disassembling the collar etc.? The rest of the column seems fine but I'm worried about the sloppy shifting when messing around drag racing etc.. Thanks for any help.