Correct Water Pump For Very Early 1970 454

[Bob P.]

I have a 1970 454 serial number 870, so it is a very early car. The water pump that was on the car is GM # 3856284. I looked in the TIM&JG and it says that it should be a 3940960. I also looked in the "Corvette by the numbers" manual and found that it said "early production cars could have had the 3856284 or 3940960 water pump. Since the engine will be rebuilt and the pump as well, I don't want to rebuild a pump that will not pass judging, but I feel the 3856284 is the pump that came on the car. Not sure what to do. Which pump is correct? What should I do? Thanks for you help!

[Terry M.]

Re: Correct Water Pump For Very Early 1970 454

I have a 1970 454 serial number 870, so it is a very early car. The water pump that was on the car is GM # 3856284. I looked in the TIM&JG and it says that it should be a 3940960. I also looked in the "Corvette by the numbers" manual and found that it said "early production cars could have had the 3856284 or 3940960 water pump. Since the engine will be rebuilt and the pump as well, I don't want to rebuild a pump that will not pass judging, but I feel the 3856284 is the pump that came on the car. Not sure what to do. Which pump is correct? What should I do? Thanks for you help!

And the date code of the pump you have is???

[Bob P.]

Re: Correct Water Pump For Very Early 1970 454

Terry, You are correct. The pump is from 1965.

[Terry M.]

Re: Correct Water Pump For Very Early 1970 454

Terry, You are correct. The pump is from 1965.

You give me too much credit Bob. I had no idea of the answer to your question, I was simply offering a route to an additional clue to the mystery.

[Joe L.]

Re: Correct Water Pump For Very Early 1970 454

Terry, You are correct. The pump is from 1965.

Robert-----


If you can find a 3856284 that's dated within 6 months of your engine's build date, it MIGHT have been originally installed on your car..

More likely, it would have been less than 4 weeks from the engine's build. No matter; I don't think you'll find a '284' pump so-dated.

If you find a 3940960 pump casting dated within the same parameters I described above, it could have been originally installed on your engine. A so-dated '960' pump I think you'll be able to find (although it might not be easy since the '960' is one of the more rare big block castings)