Somehow your alt. is not connected to the battery or not returning to ground. If you are going through an ammeter it might be a bad shunt. You should have heavy gauge wire from the alt to the battery & like said before, a good ground. Check connections at the starter post & any junction blocks. Check any fuseable links. They can be burned out inside the insulation & you cant tell by looking. If your old gen. type regulator is still in the circuit make sure you are not trying to go through the cutout.
George
