1971 water pump

[Paul Y.]

Re: 1971 water pump

As always things take a little longer but here are the photos as promised Patrick. I was off on the date. It looks like it is 1/21/1.

[Patrick H.]

Re: 1971 water pump

Thanks Paul.

[Mike E.]

Re: 1971 water pump

Isn't that actually I 21 1, which computes to September 21, 71? Not trying to be difficult, but that's what I see. It's not the original to the car, is it? I would expect to see a letter rather than a numeral in the first space, and that's why the first and last "1"s are different--the first is an "I" while the second is a "1".

[Paul Y.]

Re: 1971 water pump

It is original to the car and that can very well be because of the strike that year. I think you are right on the first letter as I.

[Mike E.]

Re: 1971 water pump

Paul,
I'm still a little confused by all this. Is your car a 71 or72? The strike was Sept-Nov 70, affecting the 71model year production. The pump you have pictured is September 21, 71. fits a 72 model year car.

[Paul Y.]

Re: 1971 water pump

Paul,
I'm still a little confused by all this. Is your car a 71 or72? The strike was Sept-Nov 70, affecting the 71model year production. The pump you have pictured is September 21, 71. fits a 72 model year car.

I'm confused now too. The pump came off the car from the second owner removing it. I don't have any information on what the first owner did but I have a big file of receipts so I guess when time allows I should look through and try to find if it was replaced. Maybe under warranty. It seems strange that with such a small window of 399 pumps that this one would show up on this car after all this time. My pump rebuilder thought that it should have the cast for the overflow like the later 72 had. He even showed me one that he thought was right. He had not seen one like the 399. It sure is fun unravelling the mysteries of these great old automobiles.

[Joe L.]

Re: 1971 water pump

I'm confused now too. The pump came off the car from the second owner removing it. I don't have any information on what the first owner did but I have a big file of receipts so I guess when time allows I should look through and try to find if it was replaced. Maybe under warranty. It seems strange that with such a small window of 399 pumps that this one would show up on this car after all this time. My pump rebuilder thought that it should have the cast for the overflow like the later 72 had. He even showed me one that he thought was right. He had not seen one like the 399. It sure is fun unravelling the mysteries of these great old automobiles.

Paul------


I would interpret the first character as an "I", too. Also, I've never known a GM casting of the period to use a digit for the month. Of course, it's possible it was some sort of foundry mistake. These did happen from time-to-time. In addition, you can clearly see the difference between the first character and the last character which is definitely a "1".

If it really is "I 21 1" (September 21, 1971) then it's too late for any 1971. It is possible, though, that the water pump failed very early in the car's life (e.g. November, 1971) and was replaced. At that time, the 3991399 casting pump was still being manufactured and supplied in SERVICE.

[Don L.]

Re: 1971 water pump

The "399" water pump I got for my very early August '71 built SB engine is dated "C" (March). I want to say the day was either 23 or 24. Car's up so I can't look to include in this post. I will look if someone really needs the day.

The part is not original to the engine/(model year '72) car, and when I bought the pump to correct the "plugged" unit that was on when I bought the car, I bought it from a "very well known" NCRS member/vendor. When I bought, I was advised that these parts were built in batches, so the 6 month rule may/may not make sense for a water pump. I seem to recall that I was told the next batch after March would have the pump too late for my engine build date. Since my late March unit fits the 6 month rule for me, I didn't question. I had no reason to doubt the source.

[Paul Y.]

Re: 1971 water pump

Paul------I would interpret the first character as an "I", too. Also, I've never known a GM casting of the period to use a digit for the month. Of course, it's possible it was some sort of foundry mistake. These did happen from time-to-time. In addition, you can clearly see the difference between the first character and the last character which is definitely a "1".If it really is "I 21 1" (September 21, 1971) then it's too late for any 1971. It is possible, though, that the water pump failed very early in the car's life (e.g. November, 1971) and was replaced. At that time, the 3991399 casting pump was still being manufactured and supplied in SERVICE.

Although I am about to put this to rest, as I am just happy to have a properly configured pump with the right casting numbers, I have to say that all three numbers that look like one or I are different from each other. The first one is straight up and down like a straight line, the second one is somewhat crooked and seems to get wider on the bottom, while the last one looks like a cross between a one and a seven. I wonder of a one or seven was used by mistake instead of a 0 for 1970? That would be easier to explain than an early failure. My build date on the trim tag is F13. It's a conundrum but fun to speculate.DSCN1507.jpgI am the third owner with the second owner pretty short timed. The only things not matching were the carburator and the alternator as all of the other componets and accesaries were correct. As I install the LT-1 short block, I find very few bolts even changed out. Lots of fun and thanks for the information from all you experts.