So if I getting this right, the use of original unaltered spindles were designed for a particular wheel base. However no one has commented on what happens when they are put on a different axle, or the axle is dropped, which changes the king pin centers. In my particular case I have late 40's square back spindles on a stock undropped model A axle. I have lenghtened the wheelbase somewhat, although I can't remember the final number off the top of my head. My take away is that I'm probably in the ball park akerman wise, because the later axles were wider, and my wheel base is longer but not extremely longer.