I just checked a couple of things.
Classic Performance Products uses the stock spindles, and simply mounts disc brake brackets
I've also had a look (using NAPA ProLink) at Ford 2-bolt lower ball joints
#260-1075, which appear (at least using this catalog) the only ball joints of this type.
The buyer's guide tells me that these LBJ's were used on 65-72 Galaxie 500. (among many others)
This proves to be a bit inconclusive, however, because they list both drum and disc front brakes on the '72 ... AND they list both "bolt-on" and "press-in" LBJ's.
Here is a link to all of the available NAPA catalogs (Flash Format) on NAPA e-Rack
I'm wondering if one of the Mods might pick up on this thread and post the above link to some kind of "sticky"? There' s a wealth of information in those old "paper catalogs"