[HO455]

It is my understanding that when the factory upgraded the charging system to the 63 amp alternator they left the standard 37 amp harness in place and added harness that consisted of a second 10 guage wire from the alternator that went to an insulated terminal on the core support near the horn and additional wires for the voltage regulator.

There was second terminal near the one from the output of the alternator that tied the voltage regulator into the circuit. GM expected that all of the additional loads added to the system be hooked up to the insulated terminal and not to the regular harness.

The regulator harness still only charged the battery at a maximum of 37 amps but allowed the system to handle high amperage loads like VHF radios or a rear heater in a Burban when the engine was running.

There is little information about the higher amperage alternators that were available from the factory. Although you might make a post in the Heavy Haulers section as I believe the high amperage systems were more common in the C40's and larger trucks.