What causes a squeal in the engine on a 1999 Chevy Corvette to increase with acceleration?

I have a 99 and had a nasty squeal that would be intermittant upon acceleration, I changed the belts (upper and lower) and used Gatorbacks (belts by Goodyear), and the squeal is gone.. Don't know if this is the problem or not, but it will only cost you about 50 bucks and hour worth of your time to find out. Good luck!