I hate to bring an old post back to the top, but I hate seeing information that doesn't make sense.
To address the original question, can an f-body rear disc setup be used on a G-body? Why not? From 82-92 the standard, typical F-body rear differential is the same tiny 10-bolt as the G-body. Some 85-89 F's had a Borg Warner 9-bolt, but the brakes were still the same they just used different caliper mounting plates. The earlier Delco-Moraine caliper rear discs aren't very desirable... When they work as designed they're fine, but they typically don't work as designed. The 89-92 PBR caliper system is much easier to work with and more likely to work properly.
A person would need the donor car's brakes from the caliper mounting brackets on out, and at least the proportioning valve from the donor and maybe the master cylinder. The booster shouldn't matter. Also the brake hardlines on the differential will be different and the F-body donor lines might not be the right length.
All the drum brake hardware would have to be removed, and the mounting flange on the housing cut for the disc brackets. The two existing lower drum backing mount holes will be reused and two new holes need to be drilled in the top corners of the mounting flange. The proportioning valve and maybe the master cylinder need to be changed to deliver the correct pressure variations front vs rear.
The 93-97 Fbody rear brakes are the same PBR setup, but have cast mounting brackets instead of stamped steel. They still function the same and would require the same parts. The 98-up LS1 system is quite a bit different and would require more work to adapt.
The difference in caliper mounting location from left to right only applies to the cast iron Delco-Moraine caliper system, the PBR's have both calipers on the rear side of the axle. If they need to be to the front side of the axle for clearance, theoretically a person should be able to put the left side mounting plate, on the right side of the axle housing and vice-versa.
The cast calipers on the F-body don't usually work as well as the stock drum brakes. Making the swap from the drums to cast caliper disc would be a cosmetic improvement only, unless new parts are used. Also the Delco calipers vs the PBR calipers use different master cylinders and proportioning valves. The later PBR systems use the same master as a disc/drum car with only a different prop valve.
Of course this is all free theoretical information. I know F-bodies inside out, and enough about G-bodies to be dangerous. Use this information at your own risk.
