The earlier Superduty 60 is for leaf-springs, the Super 60 is for radius arms and links. The link mount is cast into the driver side of the differential housing.
The Super 60 uses shafts with wider yokes, so it uses a different knuckle, balljoint, and u-joint, which all allow a tighter turning angle.
Here's a nice prepper, if a few years old now, below:
http://www.fourwheeler.com/how-to/transmission-drivetrain/131-0906-dana-super-60-front-axle/
