I see two issues.. that is the incorrect PS pump pulley and you do not have the crank pulley for PS. the crank pulley you have is for running the alternator and AC. there is a separate pulley for PS. (depending on which pump pulley it can either be a single groove stamped steel one or a cast iron double groove
Here is a picture of the correct "flat" PS pulley which uses the cast iron crank pulley.
http://67-72chevytrucks.com/vboard/s...d.php?t=474903
Here is a picture of the correct "bell shaped" PS pulley that uses the stamped steel single groove crank pulley
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http://67-72chevytrucks.com/vboard/s...d.php?t=474244