ball joints

I can't tell you the actual size of the ball joints, but Kelsey-Hayes four-piston fixed caliper disc brakes were an available FACTORY option from 65-72 and used the small ball joint and small bolt pattern wheels.

All 73-76 a-bodies used the large ball joint, but some slant six cars used small bolt pattern drums. All disc brakes from 73-on (RWD stuff) was large bolt pattern and used the large ball joint.