I got two new pulleys for my alt. One 2 3/4 and 2 7/8, after using the 2 3/4 car revs easier and pulls uphill nicer. A ~22% slower alt is great. Will try the next size bigger Tuesday. output is 14.1 at idle so far. I was surprised at how well this mod worked as the wp is still at full speed. Mods on test car r listed below.