Well the stock belt won't work, trust me I tired not shell out $22 for the new one but had to. I got a Goodyear belt from "The Zone" LOL.
Anyway the install is pretty straight foreward, pull old wuss 105A by taking out 2 bolts, disconnect battery wire, and voltage regulator. Use a hammer to persuade the two brass looking rivits that where the alt goes inplace for a easier drop in. you must succomb to the hammer.
So with my stock crank pulley and stock alt pulley I now have over 14V at idle with the A/C on 5, fans blasting, and the headlights on!
Moral is... good mod for ~$100 all said and done.