Squealing
 

I have a 2002 silverado 2500hd with the 6.0 v8 just bought it a week ago. I have put a bullydog tuner, cat back dual magnaflow exhaust, and a cold air intake on it. I have a question on why the motor is squealing when the throttle is being used. It is not the belts and the squealing gets louder with more throttle and it sounds like i have a supercharger under the hood. Any help would be appreciated

Bad belt pulley.