My advice if you decide on the one wire. Be prepared to install a Volt gauge. If you do not, you will have no means of keeping track of wether the alternator is actually charging! It's not an "upgrade" in my opinion if you don't add the gauge. Plus with the one wire you have to make sure you goose the throttle when you start the car as they don't kick in a charge till they reach a certain RPM. This RPM varies by internal regulator styl too from what I remember reading.
The "one wire" has a connector on the side that has a sense wire to measure battery voltage (optional) and one to drive the idiot light. My Rambler and Hornet are wired that way.
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