squareback alternator wiring in pre 70 car issue

I have a 67 Valiant small block with factory wiring. I have a sqaure back alternator (75 dart) with 2 fields but the car wiring didn't come with 2 field wires and I noticed that the 2nd field was grounded which is overcharging at idle (15.2) so I unplugged it and it reads (12.4). I also have the solid state OE replacement VR. I had the alternator and battery checked and both are good. I replaced the VR with another new one (same style) still same issue. IF I keep this sqaureback where do I run the other field to and can I keep the same style regulator or do I have to upgrade to the newer style VR and will it mount in the same place as the old style? I'm trying to keep it as stock looking as possible.

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