Water pump pulley

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I am adding power steering to my 250 6 cyl. I am having a hard time finding out what 2 groove water pump pulley I need. The original single groove pulley is #3927797af. The over all height it 2 3/4", width is 7". My double crank pulley is 1 1/8" over all. I have some pics, but can't figure out how to upload them. I found a double pulley on a 6 cyl truck 3770245cc, the gap between the grooves is just a little too wide. Google says it fits a corvette, go figure. Any help would be greatly appreciated.