I have a 1974 Dodge Challenger with a 1973 340 engine. The car originally had a 318 engine. The alternator only has a place for 3 wires to attach to it. However the wiring harness has 4 four wires that go to the alternator. 3 wires are hooked up and one isn't attached to anything. This is how I got the car. The car has a new alternator on it. I think that maybe a 1974 Challenger is supposed to have a different alternator or maybe the 4th wire should be hooked up with one of the other wires.

There is a think black wire attached with a 1/2 nut
There is a blue wire closest to the black wire and the green wire farthest from the black wire all the way to the left. The brown wire is not attched to anything. Is this hooked up right?