Correct, you'd want 73+ A-body disk lower ball joints.
ok now lets talk LCA. are all a body the same regardless of drum or disk. my car does has a set I found in the trunk not sure if there from a 69 or now they could be 73. it looks like my upper UCA are 73 ish due to the big ball joint. spindles were still connected to the UCA but I think the left was on the right and you get the picture calipers were facing to the rear of the car.
