Is there diferences between aluminum and cast iron water pumps?

I have been in contact with edelbrock on the issue with the alternator bracket and they suggested to use an after market bracket that year one sells and when you look it up it mentions for use with aluminum water pump so, the gest of the problem is when you use this bracket you are sticking the alternator out at least a 1/4 in. which in turn throws the rest of the pulleys out of whack. so my question is would using a billit set of pulleys with the aluminum water pump solve this issue? When I say billit pulleys I mean like the small block double pulley for the water pump and a triple pulley for the vibration damper or crack pulley. Any body got any ideas? I'm trying to figure a way for all these pulleys to be in line? This is all caused from the set of heads sticking out to far.

Pat Faley
1967 Barracuda notch back
Peoria IL