Re: underdrive pully
The only one I had any trouble with was the alternator pulley. The water pump and crank on mine were easy. 4 bolts each. Make sure to loosen the bolts with the serpentine belt still on though, makes it a lot easier to get them undone.
I did them on my '86 Vert, so not sure what year your car is, but should be simple enough. Couple of pics of mine......