Restoring This Car And Cant Get The Pullies To Line Up Water Pump Is Off 1/2 A Belt On 3 Diff Pumps Hate To Shim Everything Was A # Matching Basket Case Anyone Seen This Before And What Is Wrong 69 Corvette 350/300
Well, well, well. Seeing as the 1st genaration SBC only has two diferent
basic styles of water pump***, long and short nose and there is
substantially more difference than "1/2 a belt" your problem lies
elsewhere. Assuming everything else lines up the problem is going to be
with the water pump pulley. There are several different offsets used over
the years to compensate for different spacing on the accessory drive. Time
to get your exact required measurements and hit the Vette junkyard. Do not
under any circumstances "shim" the pulley to fit, do the job right the
first time and save your radiator.
On the other hand if the alignment is only slightly off, that was a common problem on GM vehicles of that era. Call it the "not giving a sh*t if they're built well as long as we sell them" philosophy of design.
*** Including variations in hub bolt pattern, outlet bypasses, etc, there are over 20 different part numbers for SBC water pumps. The only dimension I'm concerned with in this case is nose length.