[ZWILD1]

Try and really isolate the noise and make sure it's the alternator . I made that mistake with my 96 LT1 coupe. I have that alternator sitting in my parts collection. I was sure it was the alternator and swapped it out. Upon starting the car the noise was still there. It could have been the power steering pump or possibly the ac compressor. I even tried the screw driver trick and it sounded like I could hear it coming from the alternator. I would try a stethoscope or maybe removing the belt all together and turning each accessory pulley including the water pump.