QA1 K and Gen III

I would never laugh or point....but if you butt welded a piece of 3/4DD shaft to extend / adapt your factory shaft....IMO, you are playing with fire.

I have extended numerous shafts replacing only the lower portion of the 2 piece steering shaft by plug welding a piece of 3/4" DD shaft slipped into a short piece of 1" DD shaft. The 1" DD (upper portion of lower shaft) slides beautifully right back over the lower end of the top half of the factory shaft which by the way is a 3/4" DD. .....now you have a safe, secure lower that is 3/4DD at the very bottom. Cut to length (don't forget the extra safety notch) and good to go. I buy the 1" DD and 3/4 " DD shafts thru Summit, but readily available...Speedway Motors, E-bay, etc.

Position the 1" DD stub just thru the factory bearing at the lower end of the factory column tube....perfect fit.
Unless keeping the actual column tube unmodified, I normally first cut the column tube back to within an inch of the firewall plate....because I like the room.

Automatic column shifts....same /same, no problem.
I did this on Jim B's Hemi Demon /power rack / column shift years ago and currently on Nils Hemi Swinger / Passon 5-speed where room is at a premium and easy function is a must. Use the polished 3/4" DD for the lower end if going for pretty.

If you leave adequate room at the top of your new lower assembly, the shaft will remain collapsible as designed for your safety. When you want to dis assemble or remove the new lower shaft assembly, simply loosen the set screws on the u-joint / coupling and slide the lower assembly further back up onto the upper shaft inside the column.

JMO...others may vary