Drum to Disc brake swap

I've been reading posts on converting a 72 Dart from front drum brakes, to disc. As I understand, the upper control arm needs to come from the 73-76 A Body, as well as the other disc brake parts. I'm confused as to the lower ball joint. Apparently the only difference is the later ball joint bolts to the steering knuckle with larger bolts, right? So you can either use a 73-76 ball joint, or drill out the bolt holes in the early ball joint to accept the larger bolts? Is that the way to do it? Thanks!