I doubt there was a special alternator harness, except for the alternator to battery load. From the starter solenoid back, the loads should have been approximately equal regardless of alternator usage. Current flow is a function of demand by the accessories and the car; not how much current the alternator can "push". Further, Ford designed a safety factor of at least two in their wiring (where it can be ascertained by fuse size, actual current, and wire gauge size). I would suspect there's an additional safety factor for non-fused wiring, such as the alternator to battery.
Just my opinion, of course.