Which alternator 60A or 46A?

from 1970 Dart factory service manual:
slant six - 26 =/-3 amps
standard all other models - 34.5=/-3
heavy duty or Air Conditioning - 44.5=/-3
special equipment (fleet) - 51=/-3\

The fleet 51=/-3 amp alternator was mostly for police/emergency services vehicles and taxis - WHEN USED THE FACTORY BYPASSES THE BULKHEAD CONNECTOR AND RUNS THE MAIN WIRES (BLACK AND RED) THROUGH A GROMETTED HOLE DRILLED IN THE FIREWALL

Given this info it sounds like the 46 amp is the way to go if you are using factory wiring. I tried to use a 100 amp alternator and managed to fry the wires under the dash of my 70 Dart Custom. If you use the 60 amp unit I'd at least bypass the bulkhead connector. If you don't have a lot of added power demanding stuff, you shouldn't need more than 46 amps.