1972 K10 - Steering Column Shaft needs to be replaced

[Benjamin]

I mentioned this in a question on somebody else's thread, but I figured I would start my own thread. After replacing the turn signal switch, when I tightened down the nut that holds the steering wheel on, I stripped the threads on the steering shaft (above the splined section). I would like to replace this shaft, but I can't figure out what kind of replacement part I need. It's a 1972 K10, floor shift, 4-speed manual. previous owner replaced steering column with a column from a column shift automatic truck.