72 Dart Swinger Fuse Blowing (New to Older Cars)

Happy Thanksgiving fabo,

Had a chance to work on the dart some more this morning. Verified that the fuse blows only while the car is running and alternator charging. We put as much load as we could with the alternator switch off, Radiator fans, fuel and water pump, and headlights on and the fuse was fine.

When I switched the alternator switch on we saw an increase in voltage (starter solenoid to the voltage regulator ground) for a few seconds before the fuse blew.

The car remained running as normal after the fuse blew. We had the fuse out while the car was running to verify it was blown, then when I turned the alternator switch off the car immediately died.

Any idea if I can have this professionally fixed and how to go about finding someone to do this? I'm located in South Alabama.

Pulling my hair out here.

Thanks in advance all.