Thanks for the warm welcome from all. The alternator is a Remy 20040 which has three wires. I'll zing over to the electrical forum as I have other Qs too about things like removable waterproof connectors.
On a completely separate matter I thought I would mention a very unlikely sounding "attraction" for me with these old Chevy Trucks. When I was a kid I could tell the Chevys from other trucks by a sound that was made when the driver eased off the brake or clutch pedal and the pedal driven by the return spring whacked a rubber bumper into the floor boards. It was so distinctive I could tell the Chevys even with my back turned. I always liked that sound and hope to be making some of my own here in the next few months.
