See there are three connections on this alternator. One is the threaded post which would where your blue wire is attached. The other two are the field connections for a later style round back alternator. One connection would be for the green wire and the other would go to ground IF your alternator is configured this way.How can you tell if it is or not? Do they look any different? And which lead goes back to the regulator? The blue, hot energized lead (hot to key/ballast) or the 2nd green lead? Are you supposed to tape one off and ground the extra field terminal?
Website documentation and/or pictures would help please.
Like this.
This is an alternator with a single field connection and what would be original to a pre 1970 car.