Ford Repair: 91 GT- Is there any hope?, alternator pulley, worst case scenario

Question
Hi Steve, I have a 91 Mustang GT 5.0 and I bought a performance pulley set for it a while back. However by mistake, a family member/"mechanic" had the grooves (or ridges) of the alternator pulley machined off. He said it will still work but I would need another belt. I didnt want to take the chance so I left the stock one on. Is the pulley still usable? And if it is, what will I need to make it work? THANKS!!

Answer
John-

  In the interest of safety/not breaking down somewhere because you pitched a belt, I wouldn't use that machined pulley.  Is the pulley sure to cause problems?  No...but it certainly increases the possibility.  Some pulleys are designed to be used with the flat side of the belt (like the water pump, for instance).  The alternator pulley needs to be grooved to properly work.  Best case scenario is thatyour alternator probably isn't charging as well as it should.  Worst case scenario is that it will start shredding belts.  Hope this helps.

Steve