C2 66 Water Pump

[Ed R.]

I have a 327/300 I purchased that came with water pump number GM 21, 3782808, and L187. This is going in a 66 with A/C and power steering. From my old engine I have a pulley with number 3890419 and found it doesn't fit on the water pump. What is this pump and what pump can I get that will fit my pulley?

As always, thanks for you help in advance.

[Joe L.]

Re: C2 66 Water Pump

Ed-----

I think you will find that the waterpump casting is 3782608; the "6" may look like an "8", but it's a "6". There was no waterpump casting of GM #3782808.

I cannot imagine why the 3890419 pulley does not fit on the waterpump; it should fit perfectly as it was designed to be used on that pump. In what way does it not fit?

[Ed R.]

Re: C2 66 Water Pump

OK Joe, thanks. I'll check the number again.

[Ed R.]

Re: C2 66 Water Pump

Joe, I checked those numbers again and have to agree that '8' must be a '6'. Even with trifocals it's hard to tell. As to your question about what doesn't fit, the pulley center hole does not slide on the nose of the pump. I took some measurments last night and it seems the nose is either out of round or the tip has spread. It doesn't look like someone has taken a hammper to it so I'm at a loss as to what happended. The bearing is tight and moves freely. Any thoughts/suggestions?

Thanks.