KeyWestJack

What is the difference between the two? Are they specific to model years? Thanks, Jack

...Roger...

In general Corvettes don't use the long pump.

redman76

I beleive there are 3 sizes -- short, long and corvette which is between a short and long. Are you replacing one you already have? If so, measure the distance from the mounting surface to the end of the shaft where the pulleys mount. Also, measure the diameter of the shaft; they are different too. I ordered the corvette pump, right? It's a Corvette!!! I forgot that my motor is not original, so then I measured and bought the correct one (short). If you end up with the wrong size, you're pulleys will not line up with your accessories. Fortunately, I had enough forthought to compare the new to the old one before I installed and noticed the difference. Just wish I had measured BEFORE I ordered.

larrywalk

Corvettes used the "short" water pump up to about 1970, then went to a slightly longer "short" water pump by about .140 inches (block to fan flange); this pump also used a larger shaft at 3/4 inch instead of the previous 5/8 inch.

Rotonda

The short "Corvette" pump is not specific to the Corvette. It was also used in many small block powered trucks that required H.D. cooling.

UBETRUN

If a guy wanted to replace the stock water pump and pulleys on a 1970 BB, would a short water pump and the matching short aftermarket pulleys work fine? I know they will line up on the motor, just not sure if there is anything about the C3 chassis that makes it interesting. Thanks!

SC77

Newbie here, but a long time Corvette owner (77 since 1988, 86 Z51 for about 10 years which I wish I still had, and a 1969 427 resto project for about a year).

I need help on my 1977 L48:

1. Water Pump - I have read the extensive forums here on short v. long v. Corvette v. 5/8"shaft v. 3/4"shaft, but am still not sure what I need. I went to NAPA, and they have 2 basic options: 1 with 1/2-1/2"outlets and one with 1/2-3/4""outlets. Whats the deal? Both numbers are different from a stock 350 Camaro water pump for the same year. I read a reply saying I have a Long pump if I can get my finger between the pump and the timing cover, otherwise its a Short (or Corvette). I checked this, and find that my water pump actually touches the timing cover. My timing cover is not stock, and may be deeper to accommodate the double roller Crane timing chain I put in 16 years ago (about 5,000 mies ago). Any ideas??????
2. Power Steering Pump - I rebuilt the engine 16 years ago (5k miles ago), and put in bigger Comp Cam, double roller timing chain, 1.6:1 Roller Rockers, Edelbrock performer aluminum intake, new push rods, springs, stainless valves, and 58cc 10.5:1 1969(?) Chevy iron heads. When I put the alternator back on, I can no longer remove the cap from the power steering pump, as it hits the alternator bracket. I can raise it and pour fluid in, but cannot remove. Any ideas?

Thank you in advance!

Anyway - I'm in the process of getting everything back up to snuff, and look forward to talking more with everyone here!

Mike Ward

This question come frequently and I'm sometimes amazed at the self induced confusion that comes with it. Forget the 'short' vs. 'long' stuff that means nothing to the kid at NAPA. C3 Corvettes have specific water pump requirements that vary according to engine size and year of car. In specific, the shaft size is larger on later pumps, the casting configuration and number changed at least three times but most importantly the total height of the pump from backface to fan clutch mounting face is different than any other car IIRC.

There is only one correct pump for each application, and that's what should come up on the parts guy's screen. Every time I've bought one, it's been spot on. My local guy even found me one with a correct casting date on it.

If you've modified your engine with different pulleys, then all bets are off.

WRT your steering pump cap, the drive belt is the wrong length, a very common problem. The correct belt will position the pump so that the cap can be manoeuvred off.

SC77

The problem is the NAPA guy's screen shows 5 options (and I looked it up on their web site as well):

1. 1/2"-1/2" outlets
2. 1/2"-3/4" outlets
3. Severe Duty
4. New Delco
5. Aluminum (and I looked this up, but its for C4 vettes)

and they don't have them in stock,so I really want to find out what pump to order.

As for the Power steering pump belt, I can't go longer, or the pump pulley will hit the frame, and a shorter belt will leave the cap buried further under the alternator.

It's been 16 years since the rebuild, so I have no recollection of what it looked like before, but I know I could remove the cap.

snoopykissedlucy

In my quest, the Autozone pumps for my 1981 and 1976 were all wrong. The Pepboys pumps are correct....and cheap too!

SC77

Pulled the old one off - it sits about 1/32" off of the timing cover, so it should be OK.

Someone mentioned "spacers" here - but I don't recall ever seeing any spacers on my water pump. If they were about 1/4" thick,they could be a good addition.

Called and ordered a new NAPA Tru-Flow TFW-43104P Water Pump ("P" indicates High Performance, extra $25, and 3 days delivery).

I'll plug the heater bypass port (4th/bottom hole on the right side mounting flange. Its not cold in SC, so I'll let the engine get the cooling rather than my feet getting the warmth.

Heres' the Corvette section of Tru-Flow's (carried by NAPA) Water Pump Chart for everyone's reference:



Heres the TFW-43104P Water Pump ...

noonie

This is the dimension for the Corvette water pump

Corvette to 70---Block to hub----5.625"----3/4" shaft
Trucks up to 72 also

Corvette 71-82---Block to hub----5.795"----3/4" shaft


SC77

If you are going to block the bypass, then you must drill a least 3 1/8" holes in the tstat, so as not to develop dangerous steam pockets in the engine before the tstat opens.
Your pump will almost touch the timing cover, and depending on the bolts used on the back of the pump, you may have to grind some of the bolt heads thinner.
The correct pump has the 3/4" NPT port on top and the 1/2" NPT port on passenger side, but all sorts of variations of hose nipple adapters are available anyway.

I always use double rollers too.

SC77

Noonie -

Thanks for the reply.

I'll check my dims to see if my old (and new) pump is 5.795" ...

Yes - the 1/8 holes in the Tstat are critical for those who do this warm-climate mod.

I hope the new water pump has steel blades like my old one did . I had modified the vanes with a circular stainless steel plate that increase cooling flow.

I dug around and found my old "Small Block Chevy Performance" book, which states that there wer indeed 3 waterpumps use don Chevy small blocks:

1. ALL small block Chevy V8s built prior to 1969, as well as 1969 and 1970 Corvettes, used a "SHORT" water pump thats 5.545" from hub face to block with 5/8" shaft,
2. 1972-1982 "CORVETTE" Water Pumps measured 5.795" with a 3/4"shaft,
3. 1969 and later passenger car and truck small blocks used a "LONG" pump, measuring 6.900" with 5/8" shaft,
4. 1984 and later C4 Vettes used Aluminum (counter rotated) water pumps which were the same length (5.795").

I'm not sure what current Vettes use.

Now I know a lot more than I ever wanted to about Corvette and Chevy water pumps ;-)

RJ

chevymans 77

best I can tell;

the sizes mentioned are the different configurations for the hose connections.

rockauto lists about 12 or so pumps for the 77 vette

chevy only made two height pumps short and long

the corvette pump has a larger shaft and bearings (3/4")

mwm3006

Can anyone tell me if the napa tfw 43104 is a standard short water pump? I am wanting to buy a polished water pump but can't find any specs or dimensions for the 43104
Thanks

Peterbuilt

Is your Corvette a 79?

mwm3006

yes but not original engine. My big question is if the napa wp is standard short pump.

mwm3006

Right now that is what is on my 79. I'm buying a 383 stroker and want to dress it up and am having questions on polished water pump polished pulleys etc lining up correctly
Thanks