Willwood has a mustang II spindle with a bolt on steering arm designed to be switched from a front or to a rear steer, I believe the alterkation uses that spindle. The factory ball joint / steering arm will not work properly that way.
If you have ever drove a vehicle that has a rack installed with poor geometry , they are not comfortable to drive it steers itself when you hit a dip in the road, and usually have no turning radius at all :