OH Joe I need #s

[Denny J.]

#1 took the water pump off my car to day, I think it was from the 1980's # 30998 3 A with a circle around the A what year?
#2Now the tester 1972 330-818 what info on this pump do you have?I know it is very rare.Take your time clock is ticking Denny
Joe do all the people know how good you are? 7:40 chicago GO!!!

[Joe L.]

Re: OH Joe I need #s

Denny-----

#1. The number sequence "30998 3 A" does not represent a GM part number or casting number. Therefore, any waterpump bearing that number is either aftermarket or a later GM PRODUCTION or SERVICE waterpump (after they went to "out-sourced" components like this). A waterpump with those numbers on it was NEVER originally used on any 1955-82 Corvette. I consider it highly unlikely that it was originally used on any 1984-91 Corvette, either.

#2 You are correct about 330818; it is definitely RARE. In fact, it's so rare that I can't find any information that it ever existed. Now, that's rare! Of course, it's possible that it did exist and, if it did, it was very likely a casting of some kind. However, I can tell you this FOR SURE: it was NEVER a waterpump casting used on a Corvette or any other Chevrolet passenger car. There was a casting of GM #330813 (which can easily APPEAR and be INTERPRETED as 330818) which was used on Corvettes, though. It was used on late 1972 through 1982 Corvette small blocks as well as some MD and HD truck applications. It's not rare, at all. It's VERY common. In fact, if you purchase a rebuilt waterpump for a 1971-82 Corvette at your local parts store, the chances are great that it will be a 330813 casting (or, an aftermarket casting).

[Denny J.]

Re: OhJoe your good but!

#1 is an after market thanks, I do not want non corvette stuff saved in my garage for years.
BUT #2 This how good you are, I was off on the last # it is a 3.So the water pump # is 330 813 AH but this pump is rare Bill Mock called it "Hens teeth"
A non drilled bypass on top. In all his years he has seen 2 I'm look for factory upgrades at the end of 72.What I got so far Gussets around flange,Big block bearing and no bypass Its the real deal.Something NEW? for the books.

[Denny J.]

Re: OhJoe 1more ?

If it is a non drilled bypass something els is wrong.where is the bypass on the motor.or where does it not go to.I'm at work car at home.photos to night.going to be a long day.

[Denny J.]

Re: OhJoe ?

It did not go anywere it was just drilled and pluged to make the pump universal.So why did a couple {3}get passed up.rare?Denny

[Harmon C.]

Re: OhJoe 1more ?

Denny
The non drilled boss started after about 20,000 VIN as stated in the latest 70-72 TI&JG. That leaves about 7000 72's minus the big blocks that may have had the non drilled boss.
Lyle

[Denny J.]

Re: OhJoe 1more ?

Thank you Lyle 7,000 not so rare is it.But why 3 have said rare bad info?or is there something els on the pump I'm not looking at.

[Harmon C.]

Re: OhJoe 1more ?

Denny
Take off 1000 just a guess 454,s leaves 6000 that may not be tapped. If this is a Covette only part that would make them rare today even if used on other GM lines for a short period. If they were turned in as cores rebuilders may have pitched them for the ones with plugs that fit more cars.

[Joe L.]

Re: OhJoe your good but!

denny-----

You asked about a CASTING number; not a particular waterpump configuration. The casting is what's 330813. That has nothing to do with the fact that the upper boss is not drilled and tapped---that was a machining operation unrelated to the casting. The fact is that the 330813 is a common casting---no doubt about that. There's no way to tell if the upper boss is drilled, or not, from a casting number. The only way to know that is from looking at the casting or a photo thereof.

The very early 330813 casting waterpumps, those manufactured in ABOUT the period of April, 1972 through ABOUT June, 1972 usually did not have the upper boss drilled and tapped. That's because the Corvette did not require the bypass and the other application which did, some MD and HD trucks, did not start using this waterpump until 1973. So, there was no need to drill and tap the castings for the external bypass provisions for waterpumps manufactured for the 1972 model year. Certainly, the untapped castings are more rare than those which are drilled and tapped.

The rest of the aspects which you mentioned are NOT unique to the 330813. The "gussets" around the snout were used for the earlier 3991399 casting as well as all other 330813 castings, bypass drilled and tapped, or not. The bearing size was the same for ALL 1971-82 Corvette waterpumps as well as most other Chevrolet waterpumps of the 71+ period. Nothing unusual or "rare" about them, at all. Also, it is pretty well known that late 1972 Corvette small blocks using the 330813 casting usually had the bypass boss undrilled. So, there's really "nothing new for the books here", either. I don't know if judging standards for late 1972 Corvettes with 350 require the non-drilled version of the 330813 or if they're accepted either way. Actually, I don't think that it would be all that difficult to plug the upper bypass in a manner which is indiscernable after the pump is painted with the engine so as to "convert" a drilled and tapped casting to a "non-drilled and tapped".

[Joe L.]

Re: OhJoe 1more ?

denny----

No external bypass was used for any 1971+ Corvette small block. 1972+ Corvettes that have the bypass fitting drilled and tapped use a square head pipe plug to block off the fitting. The external bypass was used for the OTHER application of this waterpump----some MD and HD trucks.

[Denny J.]

Re: Joe you are the best! *NM*