A Body Disc Brake Swap 101

I am doing the '73-'76 brake swap onto my '65 Barracuda. I have purchased anything new that I can. The donor that I got my stuff from was a '72 Dart that someone else had started putting the '73-'76 setup on. Nice thing was that everything was hand tightened & came off in no time, bad thing was it was a /6 4 wheel drum car so I did not get a proportioning valve. Any suggestions on finding the correct proportioning valve, new or used? What years will work, maybe F,M,Js also? Parts cars & junkyards are almost non-existent around the Charlotte area. I already have an inline adjuster for the rear drums & a dual res. master to put on. Thanks for posting good detailed steps on this conversion; I will be following it regularly as I get mine started. Getting all the hard parts ready for powder coat so far.