Well, I replaced the voltage regulator and double checked all the wiring and grounds, but to no avail. So, I finally replaced the alternator and that seems to have fixed the problem. Readings on the ammeter are strong and consistent. Previously, if I was running in excess of 2500 rpm and turned on the lights and fan, the gauge would read right around zero. Now, with the new alternator, it reads well into the positive area under the same conditions.
As long as I was replacing the alternator, I took advantage of the opportunity to add a little more chrome to the engine.
