Rear disc kits generally suck on these trucks. An elderado caliper has a piston too small and a parking brake that doesn’t hold. You can put bigger calipers on but you lose the parking brake.
My truck had a disc brake kit with elderado calipers when I got it. Braking was terrible. I put early 80s c20 front calipers on and braking was great. But I didn’t have a parking brake. I later switched to a 2001-2007 2500HD axle in. Then I finally had discs and a parking brake.
Then I did this to the front:
http://67-72chevytrucks.com/vboard/s...d.php?t=732837