67 Barracuda Heavy Electric Load

This sounds like the alternator is not able to put out enough current for the fans, headlights, and everything else on the car. If the voltage regulator is working correctly, changing it out won't help. Relays and heavier wiring won't help if the alternator doesn't have enough current capacity, either - removing resistance will help the fans and other parts operate at their full capacity, but your alternator isn't keeping up with the capacity they're operating at already. I'd test your alternator to make sure it's healthy, and if so, consider upgrading to something bigger (along with heavier gauge charge wiring).