[Annixter]

As with others, I'd go with a 10SI case one-wire. One-wires have been around a long time, and you should be able to find one almost as easily as a three-wire if you're on the road and break down--especially if your system is good with a 63amp. Worse case, keep a spare for long trips.

One-wire is a much cleaner setup than a three-wire. A lot of people will tell you to tap into the ignition feed going to the coil for the cleanest routing, but it's not correct practice. The ignition terminal post on the switch should be dedicated to the ignition system only. Tapping into it for other circuits is a headache waiting to happen due to overloading the switch contacts and introducing unnecessary problems with your ignition supply. For a three-wire setup, you'll want to bring a dedicated wire from the accessory post on the switch or tap into an accessory circuit that can handle the additional load.

While discussing what amperage alternator your ignition system needs is a whole other conversation that requires you add up all the continuous and intermittent loads and calculate in certain load factors, my advice is to (1) do the math rather than assuming and (2) don't skimp on the charging wire gauge since the engine compartment heat exacerbates voltage drop. In the case of your battery cables and charging cable, bigger is better. You'll see all sorts of people running all sorts of amp alternators, and when you ask them how they came to that amperage, they'll tell you, "my buddy told me," "a forum post told me," "I looked at a factory setup," "some generic chart told me," "some salesman told me." Most people don't calculate the actual amperage their system draws (and add in certain load factors) and, therefore, likely run alternators with either too low of amperage or unnecessarily too high. The largest culprits of designing undercharging systems were the auto manufacturers, so I warn against assuming a 63amp is adequate.

If you're running a very bare bones setup as you suggest (no heater, radio, etc.), you're likely okay at 63amps, but you should do the math to know for sure. Also, now's the time to plan for adding a heater, radio, wiper motor, front turn signals, etc. The difference between a 63amp alternator and #8 charging wire and a 100amp alternator and #4 charging cable is around $30 versus spending a another $100 down the road to upgrade--not including having to do the labor and rewire. If you want help sizing your alternator, shoot me a PM and I'll send you an excellent thread link.