im with Fox Chassis on the wiring. i hate to say it, but atleast run another wire in parallel or something. IIRC, the stock wire is 10 gauge!!
the 94-95 alt idea from FC is what i was thinking exactly. if you are getting the alt from the parts store anyhow (your 85 amper), spend a little more (esp if you are goin have to do some rewiring anyhow). more money now, but less in the end. then run a 4 gauge cable, fuse, etc and be done.
my two cents worth. good luck.