When I put on a set of double row pulleys (water pump and crank) they were rubbing. Was all set to do a little grinding on them and a friend let me in on a little secret about them. Seems the pulleys are the same for both tall and short deck BB engines, but there is enough play in the water pump mounting holes (on the pump) that you can pull the pump up a full 1/4 inch and tighten it down, no more binding pulleys! If its realy binding you can enlarge the holes in the pump and move it a little more. I was tearing my hair out hearing what I thought was a slight knock, it was the pulleys kissing at one spot.

Have you got the right bolts holding your pump on??????? I don't think I have a 1/4 in. play in my mounting holes. That would screw up the alignment of the water holes in the block to the pump.

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1969 SS 396 Camaro/Th 400/355s.(454 now)
Not a Chevelle but the BBC guys are here!

Yeah, right bolts, there is a bit of play in lining up the water passages, there not that exact a fit. This info came from a long time rod builder of BB chevy's, was dead on in my case anyway......

I had the same problem with a set of "aftermarket generic" chrome pulleys. I ended up doing the same thing.

The play would be in the bolt holes of the waterpump, not the block, so this post is probably dead on the money.