Only 9C1's and Impalas had the G80 and disc brakes.
From:
Brake Parts List / Technical & Maintenance...
B-body rear DISC brake conversion
(fits 1991-96 B-body sedans with drum brakes, 8.5” rear axle)
Parts required to replace existing parts in rear drum brake system with OE discs from 94-96 Impala SS/Caprice 9C1:
1. Calipers & pads (1 of each item)
Caliper, OE LH & RH
Pad kit, OE FMSI D628 (1)
2. Caliper bracket, OE (2)
For RPO JL9, from 9C1 (or) WX3 (black)
3. Caliper guide pin, boot & caliper pin bolt, OE (4 of each item)
4. Backing plate (caliper mount & park brake), OE (2)
5. Park brake kit, OE (1 per car—part of item 4 with new plates)
NOTE: Items 1 thru 3 and items 4 & 5 are pre-assembled units
6. Fastener & washer for caliper bracket attachment, OE (4 of each item)
7. Park brake cable guide, OE—for right side only (1)
8. Bolt for cable guide / brake hose bracket retention, OE (2)
9. Brake hose—attaches to caliper, OE (2--1 of each item, L/R)
10. Park brake cable, OE (2--1 of each item, L/R)
11. Differential cover gasket, OE—revised design (1)
12. Strap to secure parking brake cable to axle tube (2)
13. Brake lines—for rear disc conversion, in stainless material (direct ship from Classic Tube)
Items not supplied with kit
14. Rotor (2) uses rotors for 94-96 Impala SS or Caprice 9C1
19195722 Rear rotor GM Durastop 18A656 OR EQUIVALENT
15. Differential lube/additive
16. Brake fluid