This is a welcome new part for the 3rd & 4th series Firebird & Camaro owners/ repairers.
On the outer frame as shown below lives the diff bump stops.. This will replace both for the price of less then one GM unit.
Bump Stop: Universal Flat disc Singe bolt (pr)
Body Mount Kit: 78-88 El Camino
82-92 Firebird & Camaro Master Kit.
Shim Kit: 68-82 Corvette Rear
Body Mount Kit: 76-81F - Full Body, Rad & Hardware Kit
A: Master Kit: 74-77 El Camino / Chevelle
Leaf Spring Pads: Chrysler Type 1, ribbed sides
Link Kit: Various Chev Front kits
Rear Sway Bar bushing set complete: 2011-14 Camaro
Ball Joint Dust boot Set 63-81 various GM