underdrive pulleys

[levs302]

i'm putting a set of BBK underdrive pulleys on my '95 GT. since the alternator pulley is smaller than stock, do I need a different serpentine belt? i'm planning on changing them tommorow, but i need the car to go to work monday morning so i dont want to do the swap if i'm missing a part.

 

[Black Stang 97]

on my cobra i had the steeda underdrive pulleys and the replaced the crank and alternator and water pump and used the same belt....if you have the spring loaded belt tensioner then u wont need a new belt...