I'll jump in her an tell you that the 41-46 box is a recirculating ball bearing steering box like the one used on mid 60's Ford Mustangs, to mention one, and makes the steering much easier. I have installed one on my 37 and there is a noticeable difference. It still is a little hard to turn standing still, but when moving even a small amount, the steering wheel with the 41-46 box is noticeably easier to turn. The addition of fluid steering box lubricant will also help, instead of the "gold" grease so many people pack these older steering boxes with.
To go a step further in clearing up the difference between a 37-40 steering box and a 41-46 box, the 37-40 box uses bushings to function as a steering box. In addition, even Chevrolet recognized that the 37-40 was not their best design, so they issued a repair kit which included an additional bushing to help the box work better. It still is not the box that the 41-46 box is.
Joe
