1972 Water Pump Pulley/Fan - Correct Part # ?

[Roger D.]

Mine is a 1972 coupe 350/auto car with build code B09. Need clarification on the NCRS correct part numbers for the water pump pulley and fan blade. In a Jan '08 posting Joe Lucia stated concerning P/N 3991425:

"Yes, GM #3991425 is a waterpump pulley. It's a single groove, AIR pump drive pulley. It is used in PRODUCTION for most, but not all, 1971-81 Corvette applications with AIR. It "sandwiches" onto the front of a GM #3991423 or 3991424 waterpump drive pulley and was never used for any "stand-alone" application, at all."

1. The number on my pulley is 3991424. Is this correct? My Assy Information Manual (AIM) shows the part number to be 3991423. Also is there supposed to be a date code on the pulley?

2. My fan blade has the following numbers on it:
914685 E71
3991427
Is this a correct fan blade part number for my car? My AIM show the part number to be 3991420. And I assume the E71 means May 1971?

3. For NCRS should I always go by the part numbers that show in the AIM?

Thanks in advance!!!

Roger

[Joe L.]

Re: 1972 Water Pump Pulley/Fan - Correct Part # ?

Mine is a 1972 coupe 350/auto car with build code B09. Need clarification on the NCRS correct part numbers for the water pump pulley and fan blade. In a Jan '08 posting Joe Lucia stated concerning P/N 3991425:

"Yes, GM #3991425 is a waterpump pulley. It's a single groove, AIR pump drive pulley. It is used in PRODUCTION for most, but not all, 1971-81 Corvette applications with AIR. It "sandwiches" onto the front of a GM #3991423 or 3991424 waterpump drive pulley and was never used for any "stand-alone" application, at all."

1. The number on my pulley is 3991424. Is this correct? My Assy Information Manual (AIM) shows the part number to be 3991423. Also is there supposed to be a date code on the pulley?

2. My fan blade has the following numbers on it:
914685 E71
3991427
Is this a correct fan blade part number for my car? My AIM show the part number to be 3991420. And I assume the E71 means May 1971?

3. For NCRS should I always go by the part numbers that show in the AIM?

Thanks in advance!!!

Roger

Roger-----


1) If the car has C-60, then the GM #3991424 is the correct one. If not, it's not the correct one and you should then have a GM #3991423;

2) GM #3991427 is the correct fan blade assembly IF the car has C-60. Otherwise, it's not the correct one and you should then have a GM #3991420;

3) Usually, but not always.

[Roger D.]

Re: 1972 Water Pump Pulley/Fan - Correct Part # ?

Thanks you Joe. Yes mine is a C-60 car. It is good to know that mine has the correct pulley and fan. Mine looks to be very original except for a few of the parts affected by wear that eventually get replaced via maintenance requirements, e.g., water pump, master brake cylinder, and I just found out that the starter on my '72 is a 11089427 and has a March 20, 1970 date on it (0C 20 2). Bummer. Just need to throw some more money at it!