I just installed a set of ASP pulleys on my car, whenever I am at a higher RPM they squeal like all hell for a moment. What do you think is causing this? Thanks.

 

I have the ASP pulley set, though I'm only using the crank pulley. Its never squealed. Have you checked the obvious things ? Did you install the proper short belt ? Another possibility is that your belt tensioner is worn and not able to accomodate the shorter belt. Is anything leaking onto the serpentine belt system ?