Another thing we learned during this project is that OEM alternators have "rev limits." Our high-rev antics on the dyno proved to be too much for the factory-pullied alternator. PA Performance offers replacement 130-amp units that are outfitted with 3.25-inch-diameter underdrive wheels. Note the difference between the stock pulley and the larger piece. The increased diameter basically helps lower the alternator speed, which eliminates the chances of over-spinning and frying the alternator when the crank is going wild. The PA alternator is strong enough to maintain charging levels that are more than sufficient for our Pony's electrical needs.