1955 Ford F100 with a 1962 292 V8 on 12 Volts Issue: Brand new battery wont charge, sub 13v with truck running. Yanked Alt, had it tested, tested good at O'reilly, not sure volts. Replaced external Alternator regulator. Still same issues, so I'm guessing the wiring is not as conductive as it should be? Already have brand new battery/starter cables & solenoid. Correct me if I'm missing some thing please?