Power Brake Conversion question

[66Submarine]

Oh, ok; 12.5" brake rotors on them vs 11" on half tons. I haven't actually tried to check, but I'd be surprised if there was any interchange at all. 3/4 tons were heavier trucks that needed better brakes to begin with.

MC/BB might interchange; not sure on that. I'd bet it's bigger for the larger calipers/brakes (MC, at least).

For the couple dollars it costs, I'd go ahead and buy new stuff. You are looking at what, $60 for new correct calipers and MC? I'm kind of a cheapskate myself, but brakes are kinda important...