Big bolt pattern and disk brake conversion

DionR said
Pretty sure the '73+ drum brake UCA is the same as a disk brake UCA. I don't see a different UBJ, so seems like that is correct.

The '73+ drum brake spindle got the bigger inner wheel bearing, it is different than the '72 and older and certainly different than the disk spindle. But I think they standardized the UBJ in '73 so the UCA is the same disk or drum.

I've heard that, too- but have never actually seen a big ball joint drum A body in the flesh. A few small ball joint drum cars (small bolt circle). They may exist, but until I actually see one I'll stick with what I know so far. Either way, the spindle isn't going to work for him.
Again, the parts are all different for a disc setup! (except the lca)