i have a 2002 z28 and im looking for some bolt ons before i go for the super charger. before i buy it i wanted to know does an underdrive pulley make a difference and if so whats a good buy?

 

If you going suprcharged you will need all available cooling, and the small gain in power willhardly be noticed. IMO keep the stock pulleys, you will have plenty of power.

 

Underdrive pulleys are supposed to give you a few more h.p by slowing down the belt driven components. But by slowing down the alternator, your charging system will teeter closer to the charge/discharge point when your headlights are on. Then crank up your woof-woof stereo and...just carry jumper cables and you'll be fine! But wait...you couldput on a higher amp alternator togive yourcharging systemmore juice, but a higher amp alternator just draws more h.p from the engine. Can you guess my vote? Save your money!

 

On the LS1 an ASP crank pulley is proven to be good for a 1/10th. I have had mine on for 2 years and I drive the car all the time...no charging or cooling issues ever.