Hi guys and ladies for the few of you. I just got a set of underdrives for 40 bucks stuck them on. My alt is now all messed up. Its reading 12 volts at idle i know my truck idles realy low. Around 650 to 700. Anyone else running these pulleys? Have the same problems? Would a suburbun alt work better on this. The amps should be higher I'm guessing. Thanks for your help. All yeah i need to get it fixed i got a set of e fans to go on. They will kill my alt at low idles thanks.