The big black wire goes to the starter, a large red wire (but smaller than the black) goes to the alternator. The black comes from the battery. The red comes from a junction box on the drivers side of the underhood area. There's a bunch of red wires connected to it. That's the case with my '94 4.3. Man, I hope that's right.
I went and looked at mine again on the '94. I can't find my diagram at the moment. There are two red/pink wires coming out of the alternator. One goes into the front passenger side area. It looks like it goes to the group of wires that goes to the lightbulbs in the front. The other wire is as stated. It connects to about 3 other red wires in the junction box. I wonder if the 2 wires should be connected and ran to the alternator? Are either of them long enough to go to the alternator? It might be wires that did go to a junction box at one time.