Most of them did not have large alternators, either, and some of the big ones had the factory bypass, known as the Police/ Fleet / Taxi wiring.
My 70 440-6 RR managed to "eat" the bulkhead terminals way way back about 1973 or so. Of course Al Gore had not invented the internet, yet, so I drilled out the wire holes in the connector and doubled up some larger gauge wire and fed through there. I also SOLDERED THE STUD CONNECTIONS in the ammeter, (to the shunt) which very interestingly, is documented by someone else in "today's" generation.
I've seen at least a dozen pickups with melted ammeters which had had such things as driving lights and or winches added. Another "biggie" was snow plow hoists, which were operated by large electric motors.
