Mine seemed to charge at 1000-1200 rpm I think. I don't have the car any more so I can't tell you the pulley size. I ran water pump, fan, magna fuel fuel pump, MSD 7al2. I'd run the fan and water pump after each pass to cool it down and never put the battery charger on in two years. This was with the altenator off the 90's dodge pick-up

Last edited by 80arrow; 01/27/13 10:03 PM.