Kelsey Hayes SBP disk break set, what's it worth

Hey all, I'm wanting to sell my factory 72' Kelsey Hayes small bolt pattern disk breaks in favor of 73' up BBP disk. So what's my set up worth? I'd sell everything in one shot, every part that I won't need for the BBP swap will go. I have no clue what's it's all worth but I keep hearing that it could be worth a good chunk of change.