came from installing it its oficially 1 inch longer belt that is needed. Diferences it revs a little bit quicker the voltage now fluctuates more (yes I have a cobra radar that has a built in voltimeter) and i remember that when running the lowest the voltage will got was 13.0 now when braking it goes down 12.8 or 12.6 but running y fluctuates betwen 13.8 and 13.4 like normally did without the alt pulley