If you had a 53-4 motor the pulley on the waterpump is pressed on and cant be changed easily. If you have a 53-4 motor the waterpump will be higher on the block with a plate behind it and on the 55-62 blocks the waterpump is lower in the block and the impeller is in the block. To give you advise on what to do on the pulleys the year of block must be known but if its a 53-4 someone might have had the crank pulley off and not in all the way or had the waterpump rebuilt and the pulley is not in the right place. You might have the wrong generator on it also,take a ruler or straight edge and see whats not lining up. If someone put in a 55-62 motor they might have shortened the waterpump and dont have the hub on right or the wrong pulley. If thats the case you need to contact jim carters or patricks and get a shortened pump with pulley. I hope this helps

1937 Chevy 1/2-ton pickup