I have a set of underdriver pullies that I was going to put on a friends car when He asked me if he needed a different belt. When I did mine on my 5.0 I didn't need to get a different belt. He said that he was also told that he would need a bigger rad because the cooling not be as good. I told him that the pullies wouldn't affect his cooling that much to where he would have to worry about a bigger rad. If he needs a different belt is it bigger or smaller?

 

You wont need a different belt. Your cooling will be fine. Hopefully you have non piggyback pulleys. [&:]

 

I don't think so but what if it is?

 

Piggyback pulleys can do serious damage to your engine if not balanced properly. IMO, I would stay far from piggybacks alltogether. Get a set of steeda`s and you will be fine.