4.6l underdrive pulley

Probably about 4-8rwhp. They don't help our cars as much as the 5.0's.

some peppyness to your throttle in relation the the speed the rpms climb due to less accessory drag, but still very minor.

ZERO,
I installed them and a superchip waay back in 98 and gained a whopping zero hp/tq.
Most pissed off.

Dwayne

I noticed a slight fater rev, as stated above. Car kinda felt lighter in a way. If you get them used and don't pay too much for them I'd say they are worth it. Also make sure you intall them correctly, know how to put the crank pulley on with the starter bolt and then switch to the TTY bolt with correct torque and RTV sealer in th key way. Those people who have problems with UDP's usually are due to installation error. I hope I didn't open a can of beans there because you didn't ask if they were good or bad, just how much hp.