1972 LT1 water pump

[Tim G.]

Is the correct part number for a 1972 LT1 water pump 3991399 or 3300819? The engine is stamped June 9, 1972 and it has air conditioning.

[Patrick H.]

Re: 1972 LT1 water pump

Is the correct part number for a 1972 LT1 water pump 3991399 or 3300819? The engine is stamped June 9, 1972 and it has air conditioning.

It's not 3300819, that much is for sure. Take a look at these threads: https://www.forums.ncrs.org/showthre...ghlight=330813

https://www.forums.ncrs.org/showthread.php?71506-Do-you-own-a-1972-with-serial-number-over-19000&highlight=330813

https://www.forums.ncrs.org/showthread.php?103214-1972-Corvette-Water-Pump-Usage and I can't put a line break between them due to a computer glitch at work that won't let me hit "Enter" on this web site. There are 3 links.

edit - hopped onto my ipad to fix the links

[Tim G.]

Re: 1972 LT1 water pump

Patrick, thank you. The links worked great. Unfortunately, the only item ever changed on this car was the water pump. It figures it's a rare one. It appears that 330813 is the safe bet although 3991399 would probably work, too.

[Patrick H.]

Re: 1972 LT1 water pump

Patrick, thank you. The links worked great. Unfortunately, the only item ever changed on this car was the water pump. It figures it's a rare one. It appears that 330813 is the safe bet although 3991399 would probably work, too.

Good luck finding a 330813.
You're better off with the 3991399 as you won't lose points, and you can actually find one.

[Tim G.]

Re: 1972 LT1 water pump

And I'd have money left over for gas.

[Joe L.]

Re: 1972 LT1 water pump

Is the correct part number for a 1972 LT1 water pump 3991399 or 3300819? The engine is stamped June 9, 1972 and it has air conditioning.

Tim-----


For your car's build date, I think that either a 3991399 or 330813 waterpump casting could have been originally installed.

Given this, if it were me, I'd assume it was the 3991399. That's because, in my opinion, it a better looking, "cleaner" appearing waterpump. The 330813 has that large, clunky-looking, pipe-plugged, unused upper boss. I've always just hated the way this looked on a Corvette engine------sorry 73-82 owners.

[Joe L.]

Re: 1972 LT1 water pump

Good luck finding a 330813.
You're better off with the 3991399 as you won't lose points, and you can actually find one.

Patrick------


If you mean finding a 330813 with a date which "works" for a June-built 1972 will be tough, I agree. I believe such pumps exist, but they might very well be difficult to find. However, if you mean that a 330813 is GENERALLY hard to find, I don't think so. This casting was used for quite a few years for Corvettes (L1972-82) and MD/HD trucks. It was also available in SERVICE for many years after its PRODUCTION use ended.

Actually, I've always been surprised that the 3991399 was not a lot more difficult to come by. This pump was used for less than 2 years on Corvettes and some MD/HD trucks and no other applications. The last use was more than 40 years ago.

[Patrick H.]

Re: 1972 LT1 water pump

Patrick------


If you mean finding a 330813 with a date which "works" for a June-built 1972 will be tough, I agree. I believe such pumps exist, but they might very well be difficult to find.

Yes, that's exactly what I mean.
Bill Mock's photo in one of my links is the only one I've seen other than a fake one (drilled boss filled and filed).

[Joe L.]

Re: 1972 LT1 water pump

Yes, that's exactly what I mean.
Bill Mock's photo in one of my links is the only one I've seen other than a fake one (drilled boss filled and filed).

Patrick------


Yes, the undrilled and tapped 330813 is EXTREMELY difficult to find. Generally, it could have been used within the date period correct for this car.

One thing that I believe makes these hard to find: in addition to the fact that this configuration was used for only an extremely brief period of time and for extremely limited applications (i.e. very few ever made), I'll bet than when commercial rebuilders came across one of these castings, they drilled and tapped the boss to make it usable for the applications requiring the external bypass or heater hose connection (i.e. MD/HD trucks). So, the few that ever existed were thus converted to the later style.

[William M.]

Re: 1972 LT1 water pump

I have two rebuilt "real" 330813 water pumps for late 1972 Corvettes with 350 engine dated D182 and E52. They are super rare as I've only had four others since 1978. See pics of the D182 that shows the untapped boss. Bill Mock (93)MVC-021S.JPGMVC-022S.JPG

[Patrick H.]

Re: 1972 LT1 water pump

I have two rebuilt "real" 330813 water pumps for late 1972 Corvettes with 350 engine dated D182 and E52. They are super rare as I've only had four others since 1978. See pics of the D182 that shows the untapped boss. Bill Mock (93)[ATTACH=CONFIG]50315[/ATTACH][ATTACH=CONFIG]50316[/ATTACH]

Nice Bill. Thanks for posting.