Pirate4x4.com has lots of brackets to convert 73+ front C20 disk rotors and calipers to the rear. See the ruffstuff link for the Eaton brackets.
One issue is the parking brake goes away. In some (all?) cases you can use Eldorado rear calipers, but they're rumored to be finicky, expensive and hard to come by. See the pirate link for eldo calipers info, or search pirate.
Examples
https://www.ruffstuffspecialties.com...g/EHO5272.html
https://www.ruffstuffspecialties.com...og/BoltOn.html
http://www.pirate4x4.com/forum/chevy...n-e-brake.html