68 Barracuda front disc brake conversion and suspension upgrade

Sorry, you already answered this above. Except if you kept the original spindle. Sounds like if I go to the large bolt pattern I need the big ball joint?
a lot of the aftermarket kits use the small ball joint and/or drum spindles.

ball joint taper adapters exist so that you can run the small ball joint with the later spindle that takes the large joint.