I was talking about the brown wire that's in the two wire plug on the internal reg alt. The external reg is long gone. When I ordered the M&H harness, I asked them to wire it for the more modern internal setup and the external reg wires were omitted. IMO, M&H makes the best harnesses. I also have a 66 El Camino and a 66 Chevelle and they're both wired front to back with M&H stuff!
Anyways... after digging around in my tool box I found a 20A fuse, plugged it in place of the 30A and I'll be damned - it didn't pop! I have no clue what happened to cause the original problem but the 20A is holding. I guess I'll have to keep an eye on it. Maybe I had a bad batch of fuses? Maybe they were stamped with the wrong amperage?