just got some new aluminum pulleys for a short water pump, i have a 74 with a 350 5.7l, the whole in the center of the pulley is to small and the 4 holes for the bolts are closer together then mine, does this mean i have a long neck water pump??????????? thanks

 

My understanding is that the BB's have the long and short waterpumps. I believe that the SB waterpumps are the same size. I can't explain why the holes don't line up though. It may have something to do with the volume of water that the pumps are designed toput out, as to what application.
Could also be determined by how many accessories are run off the water pump pullies.

 

Check this out:

http://store.summitracing.com/partde...p;autoview=sku

If you read the notes:

Notes: Will fit 1955-1974 Corvette models with 5/8 inch shaft. Bolt circle is 1 3/4 inch. Pulley depth 2.75 inch.

When pricing my water pumps, I came under the assumption that the little nub on the end was bigger on a Corvette, and when I actually disassembled my old one, it has, like, a plate on the back of the little turbine inside, I guess to prevent cavitation, so maybe it has a bigger bearing or something, but the Corvette def. lists a different water pump part number than a "standard" short water pump at the parts store.