66 Barracuda rear disk setup

Very doubtful that you will find a kit with the sbp.Stainless Steel Brake Corp at one time had the rotors with both bolt patterns. Sorry but they are out of business.
I would think that you can use a bbp kit and have the rotors redrilled for sbp.There are many things to consider if doing this such as the center hub is larger than the sbp so precise measurements will have to be taken to the machine shop.Maybe they can make a hub centric bushing or something to make it work.Just a thought.