power and manual steering box difference

[1970C10truck]

Im going backwards in my build Im ditching the power steering for a manual setup in my 70 C10. I have heard that it was a direct replacement for the 2 different boxes and that one or the other boxes are shorter than the other and the shafts that hook up to the steering column are different diameters etc. The list goes on and on of all the conflicting information I have been hearing. The only only things I think I have found out so far that is true is that one is the box will bolt up to the frame and two the pitman arms are different.

Can someone tell me what the differences are between the 67-72 manual and power steering boxes are. The latest I heard was that the shaft was smaller in diameter is this true or false?