Bwebb Stang

Hey i bought some underdrive pulleys off of summit racing for 69.95 for my 91 fox when i got them the alternator was the same size as the old one the water pulley was quite a bit bigger and the crankshaft pulley was about half the size i have never had underdrive pulleys so i was wondering if that is all good. what kind of horsepower has anyone gotten from these pulleys. thanks

gspfunk

They're supposed to be like that to slow your accessories down...that's how they free up HP. If your alt. pulley is the same, you shouldn't have idle issues like some do.

mattdel

thats how its supposed to be. btw, you won't really get any noticable power out of it, they only free up the drag placed on the motor from the belt system.