Both the alternator and regulator are new. My volt guage fluctuates wildly from 12-14.4 volt. Sometimes at idle it will sit at 12 and I have to rev the engine and it starts charging again. The needle will then bounce from 13-14.4. My headlights will flicker badly when this happens. There also seems to be a lot of drop when I use the signals-about 2 volts. VERY rarely will it sit steady at 14.4 and seems to only do this when cruising. I ran a separate ground from the alt to the battery and did the same to the regulator. No difference.. Anyone experience this?
I have had similar problems and even had bad alternators new in the box. While no expert, I would suggest the regulator is faulty in this case. I had several issues with my 65 when using the original set up so I upgraded to the built in regulator and omitted the external one. This solved all the problems and in particular, headlights flickering at idle.