Need to ordrer a high volume water pump for a 79. Do they use long or short style.

 

Neither. The small block Chevrolet engine used one of 3 water pumps over the years. They are referred to as short, Corvette, and long. The short and long pumps used a 5/8th inch diameter pilot shaft at the fan attachment. The Corvette pump used a ¾ inch diameter pilot shaft to mate to the fan. Measuring from the mating surface to the block to the point where the fan attaches the pumps measure;

Short – 5 5/8ths

Corvette – 5 13/16ths

Long – 6 15/16ths

The GM part number for an aluminum high volume Corvette pump is part number 14011012. They are still available from GM.

 

How did the GM aluminum water pump perform for you????temp. drop???
THANKS

 

Glad someone asked the question about water pumps - was going to ask last night but forgot

 

Gee, I'm slow in my old age. This post dropped to page 4 before I got around to responding.

I bought my GM water pump from the GMPP web site. The pump looked like a good buy with a high flow and a lug for a cam stop. The listed price was 85.00 plus shipping. I paid with a credit card.

When the pump arrived I noticed that the shipping charges had been 7.80 but the charge to my card was 101.00. A quick call to GMPP got me the response that "Well any other charges were handling fees." Nowhere on the GMPP site did they mention handling fees. There is also a notice included in the package that warns that there will be no returns for any reason, including wrong part and shipping damage. I guess if they sent a wrong part then I just bought a wrong part.

Looking over the pump I find that the casting is of extremly poor quality. There are grind marks at the mold split that must have been done with 10 grit sandpaper! The depth of the scratches measures .030 deep in places. The cam stop lug is just that, a lug. The lug is not drilled or tapped at all. The surface is not flat enough to drill it before sanding the lug flat.
On the plus side, there are enlarged passages in the pump.

Last night I installed the pump. There were no disclaimers about it on the GMPP web site but I discovered that the pump will not fit due to my use of a GM 8 inch balancer. After cutting down the cam stop lug that I had spent an entire evening making usable I was able to install the pump.

I still have not run the engine to see if I get any temp. drop.