[Timmano]

im buying a underdrive pulley kit would i need to buy a new belt? or will the one i have on her fit with the pulleys?

 

[poof505]

u need to buy a new one

 

[Cricket]

If you install the crankshaft pulley then yes, if you don't then no. The waterpump and alternator pulley can work on the standard length belt, but the crankshaft power is what frees up the power. Alternator is an overdrive pulley which affects hp and tq in no way but keeps all your accessories running properly, and the waterpump pulley is good for all of 1 hp and 1 tq if that. Other than that it just looks better under your hood.