Besides Dr Diff, who makes Disc Brake kits for 73+ 10" drums spindles? Dr Diff has been out of them for awhile and I'm not quite sure when/if he'll bring them back. I'm not looking for a brake kit now, but it would be nice to know my options since I already have the spindles.
http://www.doctordiff.com/viper-caliper-mounting-brackets-for-mopar-drum-knuckles.html