Is this a street car or drag car?
If drag only, you can use a stock water pump setup and just use the cheap Moroso water pump drive kit to turn the factory water pump.

If street driven, take your water pump housing and have the back of it (the block mounting surface) milled down the thickness of your motorplate. Or you can use a crank pulley spacer (the thickness of the plate) to push the pulley out so it lines up w/ the water pump pulley.
There are a lot of different factory pulleys out there with different offsets.

I'm no help on the factory alternator...I went w/ a low mount GM alternator setup.