What are people's opinions of underdrive pullies? I am looking at getting a set for my 97 4.6L. I am a little concerned about battery charging my commute to work is only about 3.5 miles so the truck doesn't get a lot of time to rebuild charge. I have looked at Troyer and Mac and the troyer set is 2 pullies for $189 where the Mac is thre epullies for $129, what is the difference? I am looking to add some more Hp and need other ideas, I already have a MAC intake and have gone with straight pipes post cats. Being that the truck has four friggin cats, the exhaust is likely to be choked by them, but not sure how much I can do and still get through CA emissions.

 

I have never been a fan of the pullies, but some people here like them. I found them to cause me inprevious vehicles cooling and charging problems. When I did use them, I only used the crank pulley to underdrive the whole system instead of crank, WP, and alternator