Thinking about converting my 68 with rally gauges from external to internal regulated alternator. If I use one of the kits from American AutoWire or M&H, will I need to rewire anything else to keep the GEN gauge working? I am looking at a 12SI three wire alternator.
All you should need is the wire harness kit. A 12SI is fine, but you might want to consider going to a CS series. That's what I have. Especially if you decide to add any more electrical accessories like electric fan, radio amp, fuel injector conversion, etc.
I put a 140 amp 12si on mine and it works well, runs the fans, heater, lights etc. Don't have a boom box car so no amp though. Just disconnect wires from the regulator terminals 3 and four and splice them to alternator terminal wires two and one then connect the output cable. Disconnect and tape off the #1 & 2 regulator wires. # 1 is the alternator on/off terminal and #2 is the voltage sensing terminal. # one goes through the idiot light in the dash or a resistor wire if you have gauges. If you experience run on after you turn the ignition switch off put a diode in the # 1 wire.
