Shad, a high output alternator needs to turn fast, about 8,000 rpm to put out the rated output, and they don't last at full output. Another problem is the single belt going around 3 pulleys can't deliver enough power and gives a lot of troubble. On the boat I made a 9" 2 grove pulley that ran only the alternator. The belts didn't wear much, but due to heat in the engine compartment they were shot in 2 years. The alternator diodes failed prematurely too. I carried 2 spare alternators and sets of belts. The alternators I used were Powerline 190 amp cold and 165 amp hot rated. These are built in a large Ford style housing with a big bearing at the pulley end. My preference if I was doing it over would be a Leece Nevill 200 amp. This is a much larger unit, not a souped up car alternator.