The stuff you pictured looks like it's useable. Are there any part #'s on any of them. I pretty sure the shackles will work, as they are pretty universal, the hangers I'm not sure, but check for a part # stamped into it (Bell Tech is pretty good about stamping there stuff). The flip kit is certainly a different kind than I'm use to seeing, but I don't see why it wouldn't work as long as the curved piece (which actually goes around the bottom of the axle when in the flipped configuration) fits tightly to the axle tube and remember the offset hole goes to the front. The spring perches and u-bolts should work as long as they are for a 3" axle tube as well. It looks like that c-notch kit is for the 73-87 frame rail because of the 45 degree"ish" relief, but without a part # I can't tell you for sure. As for the coil springs, how much of a drop are they suppose to provide? As long as they are the same overall diameter (not the actual coil, but the entire spring from "front to rear") they will at least fit and can be "modified" if they don't provide enough drop (read...CUT).
BTW...Here's a link to a flip bracket that I personally know fits our year trucks
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http://cgi.ebay.com/ebaymotors/73-87...Q5fAccessories
Good luck and keep us posted on what you decide to do.
Ed