From looking at your photos, it looks like the alternator is indeed under the bracket with the solenoid on it. From what little I can see of it, it is probably a 105 amp alternator. The amperage should be stamped on one of the mounting ears of the alternator. I would try to remove that bracket to get at the alternator--a silly question, does the alternator have a seperate belt, and is it there?
Also, a wire going from power to ground would not be conducive to proper electrical operation, try removing the "ground" wire, and see if you voltages improve, although I would think it would have fried off something somewhere if it was indeed a ground with all the hot wires with it.