The pullies are your accessory pullies. You see them by opening the hood and looking down at the front of your engine lol. Post a pic and we can probably tell you if you have aftermarket stuff. Would be water pump, crank and alt pullies.
2000 Mustang GT Steeda build #48. Bolt ons, suspension, Novi 2000.
Just because I give you advice, doesn't mean I know more than you. Its just means I've done more stupid ****.