McNasty11jm

i wanted to get a set of underdrive pulleys and ive heard before that it is not neccersary to change all of the pulleys that are on there now...is this true? cuz ive heard one of em is a pain to get off and i thought i have read somewhere that one of em isnt neccesarry to take off

PJB

None of them are really that hard to get off.
The one most people leave off is the alternator pulley because it doesnt charge as good with the underdrive pulley on it.

ALMOST STOCK

I went withtheMarch Performance Power and Amp underdrive pulley; I've never had a problem with the stock alt charging the battery in those 7 yrs.

If you can get to a impact gun the alternatorpulley is easy got get off 95% of the time , the other 5% if the time seems like no matter what you use the alt pulley isn't coming off.
The rest of the pulleys are easy(or should be)toremove and install.

blwn93gt

you should do a 3g alternator swap. i found out the hard way when i put underdrive pulley's on my 89 notch. i was in line at the border crossing from mexico into san diego and ended up pushing the car accross the border. the car was drawing more amps at idle that the alt was putting out. didnt realize til it was too late.

PJB

Even with the 3g alternator mine didnt charge enough at idle with the underdrive pulley. I put the stock pulley back on.

1991LX5.0

you can change as many or as few pulleys as you want to underdrive, your just going to have to measure your belt legnth

shawnk007

Your power comes from the crank pulley only. The rest of the kit is to just compensate for the new crank pulley size.

1991LX5.0

im not so sure about that, the larger pulley slows the accessories down so the motor doesnt have to work as hard to turn the crank which frees up HP

shawnk007

No, the crank pulley is smaller so it is easier to turn the other pulleys, p/s, alt, smog, etc. You get a bigger alt. pulley so your not overcharging at an idle, and a bigger water pump pulley so the volume of coolant flowing thru the engine stays the same. All your power comes from the crank only.

onetrickpony

How do you measure your belt size? All I ever changed was my crank pulley.