Which lower ball joint??

Working on my 1968 Dart suspension and have determined that I have a 73 and up idler and pitman arm ( nuts point down) . Would I use 73 and up lower ball joints also? It is disc brakes but is still small bolt pattern. Thanks in advance..

If you have small bolt pattern, 4 piston, Kelsey Hayes disc brakes, your ball joint is for 65-72 A body cars, and attatches to the spindle, (knuckle) with 9/16 diameter bolts.