I have a set of SSBC Rear Disc Brake Rotor Kits. I have had them on the car a few years but I only have a few thousand miles on them. The pads are the original pads so you can see how much pad is left. The rotors are 11.25" and Im pretty positive this is the kit A125-26 Rear Disc Brake Conversion Kit, GM-10 & 12 Bolt . I have everything except the flexible brake lines. It is also missing 1 of the long bolts that attach the caliper to the bracket ( I didnt realize this until I removed them) Im sure you can get that one bolt easily. They work just fine, I just updated everything to a Wilwood kit so I removed these.

SSBC website says they work on any '62-'77 GM 10 bolt or 12 bolt

Asking $400 + shipping