Alternator Question

Yes, Looking at the schematic I should have only two wires. The terminal on the back marked "ground" is not used correct? or do I ground it to the alternator itself?
There are three marked or named. One small terminal marked Field, One big lug Battery, One small terminal marked ground.

No electrical changes other than a electronic ignition have been made to the car. 96% original. Stock style regulator but electronic not mechanical. Otherwise also old.

John B.