I need to make more clearance between my waterpump and radiator to move my engine forward.  I have electric fan so I was thinking of getting a short water pump and pully.  My long pump measures 7"  The short is 5.625.

Will getting the short pulley with the short pump ensure my alternator and power steering pump pulleys are still aligned?

It is 1981 chevy 305.  

getting the short pump should work fine..i built a 305 with a short pump and used the stock alt and power sterring and it still worked fine with my electric fan  

I take it that your electric fan is mounted behind the radiator, ever think of making it a pusher style, it might be easier to move it in front of the core to get your clearance.  

What application did your short water pump and pulley come from?  On Rock Auto .com I can get a cardone brand for $29 intended for 91 Corvette.  It looks like the flange that mounts the pulley is same.  Only concern I have is that I thought the vette's had serpentine belt system.  If the pilot hole is larger diamter I can deal with that by drilling out the pulley hole with a lathe.