Anyone tried this rear disc kit before?

Never liked the GM rear calipers that the piston spun out & also acted as a parking brake. They just didn't last after a couple years. (I was a mechanic & have first-hand knowledge of this) Mopar Action has articles on swapping rear disc brakes from late model Mopar's (Jeeps & such) over to classic Mopar's I believe. The parking brakes are inside the rotor hat, just like a drum brake set-up.