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.
Master Kit: 67-73 Mustang
Engine & Gearbox Mount Set - Short & Wide - (Chrome) (S.B. Chev)
65-70 Impala / Parisienne Major Master kit
Rear Strut Rod Bushing: 84-87 Set: 84-87 Corvette
Body Mount kit: 68-72 Chevelle, Cutlass, Skylark W/Hardware Kit
Sway Bar Bushing Kit: 86-96 D21 Ute 23mm
Shim Kit: 68-82 Corvette Rear
Bump Stop Universal (red or Black) - Pair
REAR: Control Arm Bushing set: 65-1977 El Camino / Chevelle-
Control Arm Bushing Set: LOWER Fits 90-96 300ZX