Darryl, Cambo's bellows frames are modified lens boards. AFAIK, only SC boards fit SC function carriers. Your 5x7 SC has a 4x5 SC front standard and a 5x7 rear standard, therefore wants a tapered bag bellows.
FWIW, I faced a similar problem -- 2x3 SC front standard, 4x5 SC rear standard -- and didn't want to buy an expensive Cambo-made tapered bag bellows to suit. So I made my own, had to sacrifice two perfectly fine boards.
The first link in this
https://www.largeformatphotography....to-look-for-information-on-LF-(mainly)-lenses discussion is to a list of useful links. The DIY section has directions for making bag bellows, including mine.
Good luck, have fun,
Dan