Pulley
 

Well I started Putting my parts on my mustang yesterday I got the exhaust on,Headers,throttle body,and the car lowered. Now all I have left is the UD pulley I was wondering what kinda belt i need to get?

you can reuse the stock belt.

Really I thought you had to get. a new one

depends on the pulleys, you might be able to get away with a stock belt, if not, just get a piece of string and run it through your assembly, and of course account for your tentioner pulley being contracted.