http://www.hotrod.com/articles/64159-restoring-detailing-chrysler-differential/Bill Rollik would be a good source for correct hangers, u-bolts, and other hardware. I'm currently doing the same for a 69.5 410 Dana.
Spring finishes: heat treated steel/natural, or would be painted black. Could be either. But you might want to research that further. Mine were natural, and soaked in a corragated 4" flex pipe with 50/50 mix of evaporust. Remove the clamp hardware first, as the zink will react with the derusting process.
There are several sources for articles, mainly done by Roger Gibson and Frank Badalson, such as the one in the link. There is another good one out there, but I can't find the link. It covers the spring finishes as well. May do a search here on Moparts.
Also, back issues of Mopar Action magazine has some excellent references on concourse style detailing. Panning for Gold is the name of one of the aritcles. Rick Ehrenburg would be the contact for back issues and reference CD's.
