Race performance water pumps can save up to seven horsepower...and add power from reduced detonation!

Edelbrock water pumps

 Edelbrock Victor Series Upgraded Performance Water Pump Lineup

-Victor Series Stock Replacement Style Water Pumps: Designed for High-Performance Street. Ideal for Towing, Off -Roading, Street Rod. Available for GM LS, Chevrolet,Ford, AMC/Jeep

-Victor Circle Track Series Racing Water Pumps: Purpose made for all forms of racing. Circle Track, Road Racing, Off Road Racing, Drifting, Drag Racing. This series of racing water pumps were originally made for Circle Track but as time progressed it became apparent that the water pumps could be used in all forms of racing, so the name stuck.

-Victor Pro Series High Performance Competition: Purpose Made Water Pumps for High Output Racing Engines, street performance, and all out racing, 

Performance water pumps are necessary for racing. They are essential for towing, off-roading, Jeeps, vintage cars, and any vehicle with power add-ons like turbos, superchargers, intakes, exhausts, and others.


Computational flow dynamics, computer-aided design and machining techniques have produced remarkable results in Edelbrock’s water pumps. This graph shows the Edelbrock flow rate and a pressure increase from 23 PSI and flow of 57 gallons per minute with the stock GM LS1water pump to 33 PSI and 68 GPM for the Edelbrock 8896.


pressure vs flow          
All aftermarket performance water pumps are not created equal. This graph shows the difference in flow and pressure from an overseas pump and an Edelbrock one. Edelbrock’s years of research and development in arenas like NASCAR, SCCA, NHRA, and Off-Road Racing have created unsurpassed efficiency and reliability in water pumps. Edelbrock water pump flow rate 


Water pump damage occurs over time as heat and contaminants destroy the internal parts of the pump. Some of this damage is evident, like with leaks or noise, but bearing wear or impeller deterioration may not be visible.

If you replace the pump with one of the same manufacturer, and you put it under the same stress as the one that went bad, it is only a matter of time before the new unit fails.

 Silicone sealant on water pump gasket

Use silicone sealant very sparingly, if at all. Especially do not make gaskets with silicone. The sealant can get into the pump and cause severe damage. Many engine builders no longer use silicone sealant at all. Gaskets have come a long way, and despite what the kid at the auto parts store tells you, silicone is not absolutely necessary. With engines that require constant care, like in drag racing, many racers use Hylomar sealant. The stuff is non-drying and it allows parts to be removed and replaced without cleaning. Edelbrock water pumps utilize "O" rings instead of the paper gaskets.


WARNING!: OEM pumps are made for "normal" driving!

An automotive water pump is a precision part designed to work in a highly stressful environment. In this post, we visit how a small variation in the gap between the impeller and the pump body can cause overheating, even pump and engine damage.

Just as with an engine, a minor defect in a pump or its components can result in poor performance. A rebuilt water pump may pass a visual inspection, but the remanufacturers reinstall the same type of components that had failed before. This example can leave you thinking “Why is my motor still overheating when I just replaced the water pump?”.

Pressure flow graph

This graph from Edelbrock Performance compares the horsepower, the flow quantity, and the pressure produced by a competitor's water pump to one of Edelbrock manufacture. Coolant pressure in cylinder heads is vital in reducing detonation as the pressure increases the boiling point of the water, and it forces the coolant into the tiny surface irregularities where steam bubbles can hide.



 Stock water pump impellers are just standard stamped steel that are installed without serious consideration to the space between the impeller and the pump body. These wider, inconsistent gaps can create eddy flows and cavitation. The stock pumps have no specific flow design in the impeller or the distribution of the coolant, which inhibits flow and pressure. Photo Edelbrock Performance

At least if you must run a stock pump, get a new one from a dealer, not a remanufactured unit. Precise machining practices are essential in maintaining the hubs and shafts perfectly perpendicular to the body to eliminate excessive bearing load, noise and to reduce power losses and heat. Remanufacturers do not always bring the specs back up to those set by OEMs.

The best way to avoid problems when replacing a water pump for racing, towing, street performance, off-road, or a street rod is to purchase a new upgraded pump from a manufacturer specializing in performance parts.



A true purpose-made upgraded performance racing water pump must be designed from the ground up with purpose-designed components. The bearings, the shaft, and the body of the pump must be engineered to fulfill the purpose of the pump. Chief among those components is the impeller and how it functions with the other components of the water pump.

Edelbrock Racing water pump cutaway

This Edelbrock water pump cutaway illustrates the engineering that goes into making a performance racing water pump with the large shaft, the long high grade bearings, equalized water passages, and the CAD designed and dyno- tested impeller.

The number of vanes (fins) does not necessarily increase the pressure and flow from a water pump. It is the impeller design, its clearance to the pump body that maximizes flow and pressure. With an upgraded impeller design, you can slow down the pump speed, saving you some more power. 


Edelbrock racing performance impeller

Edelbrock's racing water pump impellers are cast of rust-proof sintered metal, and machined to extremely tight clearances. The design prevents cavitation and loss of power by preventing the water from seeping between the impeller and the pump body. The impellers are designed with the assistance of computer-aided drafting to maximize the flow and minimize power needed to turn the pump. The pumps can now turn more slowly to save more power, and maintain the all-important coolant pressure and flow.




 This calculator from very helpful in calculating pulley ratios and belt lengths. Remember to avoid slowing the water pump speed excessively to prevent loss of pressure and possible overheating.







Here’s a standard technique in testing for a low-flow situation:

1. Drain the coolant level down to the radiator tubes

2. Get the engine hot

3. Shut the engine off for ten minutes and let it set to make sure the thermostat is wide open

4. Start the engine and run it at 3000 RPM.

5. Look down into the top of the radiator tank with a flashlight, and you should see active circulation; if not, you are dealing with a low-flow situation.


pulleys 80061
Racing water pumps should not be revved over 7500 RPM. Speed reduction pulleys, AFC 80061, that reduce pump speeds by 20 percent are available from Think before installing these pulleys on a street vehicle as the pump may not flow enough coolant at lower engine speeds, and they will overheat.



Most V8s built in the '60s and '70s came with a range of power between 185-375hp. With all the aftermarket performance components available, it is easy to achieve horsepower figures much more significant than stock.  

The original design of OEM water pumps did not include the additional power and demand on water flow and pressure desired with the higher horsepower and the heat produced by modified engines. Using a stock pump on a built engine can cause spectacular failures. Again, stock parts belong on stock vehicles. Racing and high performance engines deserve purpose-built parts, just like trucks required to tow heavy loads, motorhomes and off-road vehicles.



Heavy-duty water pumps include thicker rib supports for the bearing. Those can still break if overtaxed. Always inspect the fan and blades for signs of wear. Cracks can form over time and weaken the fan blades' integrity. Bent blades can cause out of balance concerns that can shorten a pump's life.


Some advice from ASC Industries and Water Pump University

Fans, Clutches, and Spacers and reliability

The goal of any retrofit is to get the fan spaced into the shroud for max cooling, but be careful how you get there. Most manufacturers never offered a spacer and fan clutch combination. A fan spacer by itself or a fan clutch by itself is OK, but when used in combination, the outcome can be catastrophic. When you choose a spacer, be sure it is a snug fit on the shaft and never stack spacers. Manufacturers design their pumps with a factory fan and clutch, and any variation from that causes an additional load on the pump's bearing. This extra load can shorten the life of the pump's bearing and seal. Make sure that all components being used mate well with each other. Any misalignment or vibration in the components mounted in front of the pump shortens the life of the pump's bearings and seals, and in some cases, cause catastrophic failure where the housing of the pump fails - causing extensive damage.  


In What Direction, Does my Water Pump Turn?

Edelbrovk reverse rotation water pump

A reverse rotation water pump rotates counterclockwise when viewed from the front. Most engines since 1986 have reverse rotation pumps.If the belt wraps under the water pump pulley, you have a reverse rotation pump.

If you replace the water pump, keep the rotation direction in mind. As a rule, engines from around 1985-1986 and down run the water pumps in reverse rotation (counterclockwise if you are looking at the engine from the front of the car). The reason for this, in most cases, was the introduction of the serpentine belt. A good rule of thumb is if the pump drives off the backside of a serpentine belt against the bottom of the water pump pulley, then it is a reverse rotation one. Automotive water pumps made before 1985-86 rotate in a standard or clockwise direction (looking at the engine from the grill) like the engine. 


NOTE FROM THE EDITOR: Before you remove the belt from your engine, take a picture of its routing. The routing looks obvious with the belt installed, but when you go to replace it, well, things can get a bit confusing.



Gilmer belt pulleys
With a Gilmer belt arrangement, plan to run the hub near the center of the pulley. These belts rob less power than “V” belts, and they eliminate belt slippage. There are many more dimensions of Gilmer belt pulleys available than for “V” belts. Note the heavy ribs on the neck of this racing water pump from Edelbrock.




With a built engine, especially those running higher RPM, and stock water pumps, cavitation can occur at increased engine speeds. Cavitation is the formation of vapor (steam) bubbles in the cooling system. These bubbles form when the impellers spin faster than the incoming water. Even with a high-pressure radiator cap the pressure drops to zero and the low pressure creates a void at the impeller that turns into steam. The pump cannot move steam, and the flow of coolant stops.

When the steam bubbles cool they implode. The implosions create vibrations that damage the impellers, they reduce the flow, and they increase the water temperature. Performance racing water pumps like those from Edelbrock sport computer designed impellers that are run close to the pump body to prevent fluids from escaping the impeller pockets.



So why take the risk? Just buy a purpose built water pump for what you do, whether it's road racing, circle track, drag, off-road, or just towing a race car trailer with your truck.

A Stock Water Pump is Always Stock no Matter what you do to it.

“No matter how much you trim the ears of a donkey, you will never have a racehorse!” Old French saying.


Do you run a class where you have to use only stock parts? Well, you can improve your water pump with sheet metal impellers by adding a plate on the impeller to form a secure pocket for the water to accumulate. Further, drive the impeller down to a clearance of about 30 thousands of an inch with a small hammer and a socket. Race and performance water pumps like those from Edelbrock run tighter clearances than .025-", but their tolerances are super accurate, and you should not attempt those on auto parts pumps. You could also replace the bearings with higher grade ones from a bearing house.


Reducing the clearance between the impeller and the pump prevents eddy flows, and it can improve coolant flow by as much as 15% while keeping the engine running cooler. What is more, a tight impeller creates some additional pressure in the heads, further reducing the water boiling point and the risk of detonation. While these "blueprinting" fixes can help if you are on a budget or if there is no racing water pump available for your engine, you must remember that stock water pumps cannot handle racing. Engine builders never recommend them for a race or high performance application.

You can measure the Impeller clearance from the top of the impeller vane to the bottom edge of the housing raceway. This clearance is critical in assuring maximum pressure and flow. The small clearance reduces the amount of water under pressure that seeps around the impellers. Leakage at that point causes eddy flows and cavitation. Both events cause overheating and damage to the pump. The manufacturers of such precision products like Edelbrock Performance, must use precision tooling to achieve the tightest clearance possible.



Severely corroded components of a cooling system can cause overheating, leaks, and possible additional engine damage. For towing, street performance, and off-roading, use the correct amount of antifreeze or Evans coolant to ensure maximum durability and performance. In racing, use distilled water and a good all-purpose water wetter like Redline's "Water Wetter."

Rusted water pump in racing engine

The rust from this pump has probably propagated throughout the cooling system; this condition warrants flushing out the whole system. If you use a quality radiator or an original copper one, find a qualified shop with sonic cleaning equipment to flush out the radiator, the block and the heads.                         Photo Courtesy Evans Cooling



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  • Ron proctor - December 09, 2023

    Have 602 Chevy crate engine and we must run steel water pump. Do you anything for racing in steel?

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