lower ball joint diference

The diameter of the "stud" on the lower ball joint is the same throughout the years.
72 on back, DRUM brake ball joints use 1/2 inch diameter bolts, that attach to the spindle.
65-72 DISC brake ball joints use 9/16 diameter bolts to the spindle.
73-76 DRUM or DISC brake ball joints use 5/8 diameter bolts that attach to the spindle.