All you need to do in order to use the isolated field alternators (two insulated brushes) is to ground EITHER of one of the brushes, and hook your old green regulator wire to the remaining brush.
You can simply make up a short pigtail with a push-on connector on one end, ring on the other, and put under a case screw, or carefully examine the brush holders. One of them may be easier. It will have a fiber washer under the screw to insulate from the brush. One one of the brush holders, you can remove the fiber washer, and by careful selection of a metal washer, allow the mounting screw to ground the brush.
You can also use the later regulator, which is better if your old one is the old "mechanical" type, by adding ONE wire
In the diagram below, if you get the proper connector for the regulator, either cut it out of a later vehicle or I believe you can buy 'em from NAPA, hook the connector to the original regulator wires. The original green hooks to the "side" terminal as shown, and the original IGN terminal (the push on connector) hooks to the "top" terminal of the new connector.
While you are hooking that wire up to the (dark blue) splice in a new wire and run it down to the alternator and install a push on connector. Hook the original green up to either brush, (field) and the new wire up to the other one.
