Mine drives as it should, wheel return is normal. I had 4 degree for a long time, when I changed springs, the front sat lower and I could tell it needed more caster, the steering wheel was light and the truck didn't want to stay going straight. When I changed to 6 degrees, it was right back to tracking straight with out the wondering around. Caster changes as you raise or lower the front, rear, or both, my new springs kept the rear about the same height but lowered the front. I have since raised it slightly with longer front shackle plates. When at a stand still on a slick garage floor, the nose of the truck raises slightly when turning to full lock position. Zero caster will not do this, and to much caster will really raise the nose as you turn, you want just enough to return to center, but not so much you are lifting the nose everytime you turn. My front axle is also a early '50s, at somepoint in the trucks life it was changed out, probably due to the small '37 kingpins being worn out, ( it was plumbing/heating company truck in the Flint Hills of Kansas all it it's life). Start with four and see how it acts. I had to buy wide shims and cut them down, I couldn't find the 1 3/4" wide ones at the time.
FYI on steering boxes, the '41 is the same design as the '42-'46 only the roller balls change size so the cage nut and worn shaft do not interchange. Good news is, 1/2 to 1 1/2 trucks all used the same gear box, the steering shaft is longer on the bigger trucks, but since you are cutting it anyway it doesn't matter. New worm and cage nuts are available if needed. Be sure to check the lower bearing race for water damage, the steering shaft is not sealed, so any water that goes down the steering tube lands right at the lower bearing.
