After installing a new water pump on my 75 I was suprised to find that the pulley hit the water pump housing and made a loud screaching sound when I started the car. Can someone tell me the best place to buy a water pump that will fit without any problems. Also what is the differance between a short and long water pump, I think I need a long.

 

I am suprised, Napa generally has good parts.I suppose you could buy one from a Chevy dealership! All corvettes came with short water pumps.

 

did you get a corvette water pump or a standard chevy short water pump? if you got a regular short pump you will need a spacer kit for the front of the pump next to the pulley. check with napa about the spacers. if they dont have them summit racing does.

 

Corvettes only came with the short water pump. You would be very hard pressed to even get a long pump to fit on a Corvette with the radiator in the stock location. Early Corvettes also generally used a special pump with a larger pump shaft. I believe it's a 3/4" shaft as opposed to the standard Chevy 5/8" on. If you check the major vendors online catalogs they will typically list both with one indicated as the Corvette pump.

One thing I have noticed over the years is many folks install the standard (5/8") pump on their Corvettes only to encounter difficulties with the pulleys lining up or fitting the smaller pump shaft correctly in the stock Corvette pulley. Many of these pumps come with shims to place between the pulley mounting flange (on the pump) and the pulley itself. The pulley mounting flange is almost always pressed down on the pump shaft with an interference fit. What I have done in the past is check the pulley alignment without shims and then using a hydraulic press, move the flange on the pump shaft to get it into the correct position to avoid using shims. You may have to disassemble the pump to position the flange but it isn't too difficult. You can also take it to a good machine shop and have them move it for you. Either bring the old pump or a good set of measurements for them to work with.

Having said all of that, if you get a correct Corvette pump from a reputable source (NAPA should certainly qualify as one), you will rarely have a problem. But many parts counter folks are unaware there are two pumps for SB Chevys beyond the long one and the short one.

Good luck... GUSTO

 

look to see if there is a tab that needs to be grinded off on the bottom.

 

Another way to look is an electric water pump. I am switching over to a Proform 35gal pump(same as the CSR but half the price ) and then putting two electric fans on the radiator. Less pull on the engine, better pumping all of the time. Option to leave pump running even if car is not. Two fans that pull 1200CFM each. In my opinion better water and airflow all around. A little more expensive is the down side though.

 

My understanding is that there are 2 versions of the "short" Chevy water pump. One is unique to Corvettes and specific years had them - it was slightly "longer" than the "standard" short pump - I can't remember which years specifically, but yours may be one.

 

I just installed an EMP Stewart, Stage I, Hi-flow water pump and it fits exactly like stock. You can get it directly from their web site for $74, 99:

http://www.stewartcomponents.net/Mer...y_Code=ChevyS1

(P/N: 13103)

 

The AIM for the 1969 427/390 has shims shown for pulley alignment. My 427/390 has some aftermarket water pump on it that I just had re-built. It needed shims just like the factory used when it was all original equipment..Good-luck...joe

 

Bumping because 11 years ago Gusto saw i was going to have issues and he solved my problem before i even knew i had one!

Stewart water pump didnt clear the stock pulley, had to press the mount out 40 thous

Thanks Gusto!

 

Thanks for the feedback Philip and glad it worked out for you.

GUSTO

 

I believe Edelbrock and weiand make corvCorv specific pumps. They are aluminum and have some flow improving features too.

 

a certain vendor lists this pump as DIRECT REPLACEMENT for '76 with AC... it most certainly is NOT in stock form, the bolt holts are countersunk for bolt heads, and will NOT work with the a/c bracket due to when you tighten the bolts it ***** the bracket forward... there is NO reason for the holts to be countersunk... they should have been milled flat and that's all

 

 

I don't know the actual part number from the pump, I looked up what I ordered from Ecklers and it says alt code: 34982 and 25-108438-1 Stage 2 high flow

Even the picture shows the recessed bolt holes, I don't know why they are doing that, it shouldn't be done, it needs to be milled flat

 

Philip, I used some stainless AN washers under my bolt heads to the Stewart waterpump. That should provide a flat uninterrupted surface if needed for any brackets. I always like to use flat washers under bolts when fastening aluminum pieces to the engine. I use AN washers as they normally have a smaller outside diameter than the normal flat washers.

Good luck... GUSTO

 

yup, I used ARP washers for 3/8 bolts, they are the same way and parallel ground flat on both sides, worked good, just im missing 4 washers now lol