9" drum to disc conversion confusion

I think that scarebird kit looks quite shady it doesnt have the authenic look or strength... anyhow I have gotten some 73 dart upper control arms with the bbj, I have the b body spindles backing plates caliper mounting brackets for 10" slide style calipers and all the hardware from the donor car and have spent so far $215. Now I am trieng to figure out what the deal is with the separate hub and rotor assemblies and where to get them. I saw a diff post where ppl were saying they are off a crown vic...then machined down or somethin .