Funky alternator wiring- '73 Duster

You sure that is not the original alternator wire(batt)? The wire attached to your alternator now looks pretty hefty to me for an original.
^^I think this^^ It may have been damaged, or a "work around" for the popular bulkhead bypass. Frankly as chopped up as that all looks "it needs more work" Might be practically repairable and might not

If you don't have a factory service manual, go to MyMopar and download one.