underdrive pulleys

what exactly do these do?? pros, cons?

They slow down your accessories. Worth a few HP (REAL numbers vary on different cars). The biggest con i've ever heard is people with big stereos having charging problems. I have pullies on my bird but will be selling them when I get my blower put on. (for obvious reasons). I never had charging problems. Mainly because I don't have a big stereo or anything like that. I just incase raised my ingear idle (automatic) to 900rpm so it's in full charge.

Seabass

Yeah, about the biggest drawback is its hard to get an aftermarket stereo system to work well with the pulleys. It does give you more power, but it has to come from somewhere and that place is your electrical systems. I have them on the Spyder and they haven't caused me any problems.

Well in my T-Bird club alot of guys do pullys but they simply leave out the alternator pully. Others simply get a higher amperage alternator and/or have their idle adjusted (like me) via EEC-V. Every little bit counts. I dig em...but gotta lose em here soon.

Seabass