91LXmustang

ok, im going to order a bbk aluminum underdrive pulley kit, when I install the pulleys, will i have to get a smaller belt, or will the old one fit with the smaller pulleys.

n2o44

it should fit in most cases , if not you can get a custom belt a lil shorter , worst case

89muscle

underdrive pully's are bigger so you will need a bigger belt

95Stealth302

Not if you have a self tensioner on a spring, it adjusts just fine, they are made to run with stock belts. But get some MARCH pulleys, they are better deal and same quality, also, aluminum doesnt give that much more power, and I hear the coating rubs off really quickly.