Melting wires -- '67 383 with elec ignition

I'm no electrical wizard, but I have triple- and quadruple checked the wiring and it's all correct. Mallory EI distributor, no exotic parts. Bulkhead connector main feed is bypassed and all other connectors cleaned so no corrosion causing resistance. The last thing I did before this started was change the alternator, and when I turned the ignition to "on" (not "start") I fried the wire from the alternator to the electronic voltage regulator. Upgraded the wire gauge for GP, tried again and started to fry the split from that one to the ballast resistor but was paying attention so disconnected the batt before anything bad happened. Have not checked the ballast resistor's resistance value, that's next. Am I missing something in my troubleshooting? Thanks for any time you spend thinking about this.

The alt. Disconnect the "batt stud" wire and the 2 field leads(everything) from the alt & with your VOM check ohms on the 2 field male terminals(I forget the specs on them), continuity between either of the above terminals(check both) to case(should be none) and continuity between the large "batt" terminal and case(should be none). to double check take another minute & take off the fan belt & spin it by hand(in it's direction of rotation)& recheck. EDIT take a close look at your field terminals/brushes as the dead short may be right there.

Thanks, RR. When I read your post I slapped my forehead. Duh.