How much test of time does it take, De Lorean has been using the smaller pulley and it's on all the returns I get. Jan, Don't let someone scare you about the pulley's. There fine. The new alternators are made to handle it just fine. The new ones arn't 20 year old parts. New bearings,rotor,stator. Made today. Not nos parts. It's just a few MM. As far as drag on the motor. I have never seen it and run them and others all the time. John Hervey