I know that on ford 9" truck rears, you can use front bronco rotors 79ish? and brackets from speedway motors for gm metric calipers. The late 80s front wheel drive caddy rear calipers bolt to the brackets. They have a cable parking brake. Since you are using a 5 1/2 bolt pattern it may work.

84 D150 440/727
79 /6 swb D150
1964 A100 window van. Just because it has spark plug tubes doesn't mean it's a Hemi.



If ya haven't been there, ya just wouldn't understand.