Going from generator to alternator, the output kept rising from 35A to 55A to 63A to 80A (diesel) to 100A (Cadillac). The problem was that the extra torque needed made alt belt slip more and more of a problem. In 1981 the belt arrangement was changed, the alternator got its own belt off the water pump in front of the others. This allowed more belt wrap around the small alternator pulley (nearly 180 degrees) for better grip. The drive pulley was larger dia, so the alt pulley could be bigger too, more contact with the belt and less pull for a given torque (at a larger dia) trying to cause slip. Or, a smaller alt pulley gave more rpm, allowing the same output with less torque. Before pull on the water pump was from 2 directions, now that is divided into 3 which I see as an overall reduction/improvement. Besides reducing squeal, it is now possible to keep driving the car with either the power steering OR the air conditioning belt failed, water pump and alt still functioning. If the alt belt does fail, it is relatively easy to change on the road being in front and only on 2 top pulleys. I see this as a big improvement and have converted 4 of my older Olds engines to this scheme. I also converted a serpentine belt Olds engine to the 81 belts, because if ANYTHING quits on a serpentine (AC clutch, steering, even idler tension), you cannot drive the car. good luck, Bruce Roe
