alternator swap questions

I want to switch over to a 1-wire high amp alternator on my '86 GT. I'm thinking of running a big GM one. Whoops, I said the 'G' word. Anyways, there are 2 plugs coming out of the alternator right now with a total of 4 wires. If I run a 1 wire up to the solenoid on the firewall, will I have to mess with anything else, like if these wires are going to other stuff? Pretty much I'm just wondering how to convert it over. I am running a large dual speed fan and an electric water pump, I don't have any stereo equipment and don't plan on adding anything big in that department. I'm thinking about a 120 amp or so.

I don't know a whole lot about the ford 1 wire big amp ones. Any pics, daigrams, or explanations would be greatly appreciated.