So my rig still has the old style solid steering shaft and I would prefer not to become shish kabob in an accident. While the engine is out, I thought about pulling the shaft, cutting it down and milling flats for a double-D steering joint, then adding a collapsible steering shaft.

For the guys with earlier EBs, what have you done to upgrade the steering shaft?

Another option would be to find a short upper shaft that is already splined on the lower end. Those were found on '73-'77 power steer columns. This just means you'll use a different upper u-joint though. You do want a collapsible lower shaft.

I'm running a column out of a 2wd '71 F150. It's a hair shorter than the original, but works fine and got me the splined shaft I needed.

I just gave measurements and details to a bronco vendor and had them make me one. It's been great for several years now. But something tells me, you are not quite happy with just ordering something...

XJs have a nice factory collapsible lower steering shaft. I've integrated several of them into projects over the years.

Many ways to do it, cut/weld onto a stock shaft; add a splined joint at one or each end; cut/weld a double 'D' u-joint; etc... I'm actually running a Scout PS gearbox on mine, so it has the same 3/4" splined joint at the bottom for me, vs. the 13/16" EB box.
HTH, Joe