73-86 dropped spindle question

[danrduc]

I have some supposed dropped spindles from CTS in Mesa Az that are for 73 -86. I have installed them on my 69 c10 with the new ball joints, and looking at them now. I have noticed a difference in the mounting location size.
These are about 1 1/8" larger between the ball joint mounting location. They are approx. 9 1/8" compared to the old drum brake stock 8".
Is that typical? I thought these spindles were a direct replacement with the ball joint change, from what I had read? It would seem that changing the spacing between the A arms will change the entire geometry of the front end.
Anybody have any enlightenment for me? Have I misinterpreted some information, or possibly gotten the incorrect part? Thanks