You need to locate the STOCK 18'' 1955-1962 Chevy 235 fan blade.
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Your old pump is for a 1955-1962 Chevy 235 but , it has the INCORRECT 1937-1953 216 small 4'' diameter pulley on it.
The new replacement pump is also for the 1955-1962 235 . It will fit your motor but... it is designed to use the 7'' diameter pulley that is correct for the pump & it was included with the pump kit.
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The new replacement pump is also designed to use ONLY the stock 1955-1962 235 fan blade { as pictured above}.
{ you CANNOT use the earlier 216 fan blade on a later 235 water pump as the bolt pattern is wrong & it is way to small }.
You cannot mix & match incompatible fan blades & pulleys on the new replacement short shaft water pump.
Installing a smaller 1937-1953 216 pulley & 216 fan blade on a 1955 - 1962 235 water pump is dangerous as it spins the pump at twice the speed that the pump was designed for... which can result in cavitation & foaming of the coolant.... { not to mention fan blade failure from spinning the pump too fast } .
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