John, since you confirmed the parts to be from a 73 you will also need to have the upper control arms. The Ball joint is larger so the ball joint in your current ucr will not fit the spindle and the new ball joint won't fit into your ucr either.
FWIW, when I did this conversion I used the doner calipers and master cylinder as cores to get rebuilt items. I tossed the rubber brake lines and rotors and purchased new. I also popped for new wheel bearings, ball joints, rubber lines and suspension bushings.
Basically when I was done the whole front end was either new or rebuilt.