Chevelle 12 Bolt Rear Brakes

[HEEP]

Hello,
So I have been trying to work through the rear brakes for the Chevelle. I currently have a set of rotors for a 2014 Camaro that are 365mm in diameter. I'm trying to find a backing plate with the integrated parking brake on the back side of the rotor, instead of the normal caliper parking brake.

I don't mind buying used parts or even changing the brackets on the rear end housing. In fact, buying used parts and cleaning them up seems to be the process that I basically do. HAHA However, using factory parts is a goal if at all possible.

If anyone has a link to measurements, or even parts that you need to sell, please let me know.

Thanks,
Bill