Originally Posted by
Iain Mac
The 4x4 hubs take a thicker shock absorber, and the Cosworth ones have deeper lugs for the caliper to mount to and take the larger-diameter discs. Spacers can be used on "ordinary" Sierra hubs though.
Someone more knowledgeable than me will have all the details though.
I think you are getting confused. You are talking about the uprights but it's only the hubs that are of concern as the uprights will be discarded.