The jeep conversion for older trucks like my '75 (and I think trucks up to about '79) is more complicated, since the splined input on the steering box is different.
For those who want to spend more and buy an off-the-shelf solution for older trucks, I installed a new -Borgeson- steering box and replacement steering shaft with universal joints. Bought it when Jegs was running a special discount offer.
However, just make sure you get the right combination of steering box and steering shaft, since the size and spline count on the replacement box are different than your original. The new box has a larger diameter input shaft, so you have to buy the steering shaft that is used with newer boxes.
The new steering shaft was too long, so I cut the upper end down to what I thought was the right length and pinned it in place at the upper U-joint. However, after installation I realized I had cut a little too much for optimal engagement in both universal joints. Had to call tech support to find out that the lower part of the shaft has a slip joint that allows you to extend/adjust length of the shaft by about 3-4", so I made the small adjustment and now have it exactly the right length.
Slip joint and set screw was hidden by a rubber bellows when I got the shaft, so I didn't realize how easy it was to extend the length. It also makes it easier to install because you can shorten it about 1-2" for clearance to get it in place, and then extend it fully into the fittings.