see, this is where the term underdrive pully makes no sense. if you follow simple gear theory, if you have a pully that is smaller than stock, wouldent you technically overdrive the part? underdrive would be if you increased the size of the stock pully.
so, i really fail to see how reducing the size of the pully would create an underdrive state.

Lloyd

 

I think they are larger but I'm not sure because I've never seen an underdrive pulley in person. I'll let someone else confirm that.

 

I "think" the underdrive main crank pulley is suppose to be smaller, so the ratio of between the main pulley and alt/waterpump pullies will be greater.
Again, this is just what I am guessing.

 

the intention of the underdrive pulley is to slow down the other components though. Not to speed it up.

 

might be ok if you do the ford tempo alternator swap since it has a higher amperage output and given that car runs at a lower rpm?

I dont know about the waterpump and temps though

 

At the end of the day, its a waste of money on a street if your goals are performance oriented. If you just want a "bling piece" thats fine too, just realize what your're spending money on.

Generally speaking, making functional changes to support asthetic modifications is a fool's errand. However I will concede that, the stock alt sucks, and this is as good a reason as any to replace it.

 

what sort of affect would it have on the waterpump? I know everyone that sells the pulley says "decrease the chance of cavitation in the coolant" or something along those lines, but would it still pump enough coolant through the engine to cool it efficiently?