Switching to front disc brake questions

What are their problems? when I did my conversion the small ball joint spindles were taper reamed for the larger ball joint and used the wilwood kit.

The lower ball joint for the 9" drum spindle uses smaller diameter bolts than every spindle made after that. Even the 10" drum spindles use larger bolts.

I personally haven't used a set, my cars all came with 10" drums or better. But I think @AJ/FormS had a set of the 9'inchers break on him. Someone here did anyway.