Water Pumps and Conversion Kits

The Divide: 8-Bolt vs. 11-Bolt Design

The Pontiac V8 utilized two main water pump designs over its production run, defined by the number of bolts securing the water pump to the timing cover:

• 8-Bolt Design (1968 and earlier): Found on early muscle cars (e.g., 389, 421, early 400s). While original, this design is often cited as being less efficient for cooling and prone to corrosion.

   

   

• 11-Bolt Design (1969 and later): Introduced in 1969, this design offers superior flow characteristics and a better sealing surface for the water pump and timing cover. This is the preferred design for high-performance builds.

The Critical Conversion: 8-Bolt to 11-Bolt

For owners of vintage Pontiacs with the 8-bolt setup, Butler Performance strongly recommends the 8-Bolt to 11-Bolt Timing Cover Conversion Kit. This is a major upgrade that replaces the less efficient timing cover and pump with the optimized later design.

The Conversion Kit typically includes:

• 11-Bolt Timing Cover: A new or high-quality reproduction timing cover.

    

• High-Volume 11-Bolt Water Pump: A pump with an efficient impeller design (often featuring a cast or precision-machined billet aluminum impeller) to maximize flow.

    

• Pulley: Necessary to match the different fan hub height (The 11-bolt pump is typically 4.5 inches tall, versus the 4.0 inches on the early 11-bolt pump, requiring a corresponding pulley change).

    

• Water Pump Plate and Sleeves: Critical components needed for the 11-bolt design to ensure the correct internal clearance and prevent leaks.

    

• All Gaskets and Hardware: A complete set for a seamless installation.

    

This conversion is considered a crucial reliability upgrade that directly improves the engine's ability to shed heat, a necessity for stroker motors and high-compression street/strip engines.

High-Flow Water Pumps: Maximizing Circulation

Regardless of whether a builder is using a factory 11-bolt cover or converting to one, the choice of water pump is paramount. Butler Performance offers a variety of high-flow mechanical and electric options:

Mechanical High-Flow Pumps

Brands like Flowkooler and CVF are commonly stocked by Butler, featuring:

• Billet/Cast Impellers: Pumps are upgraded with precision-machined billet aluminum impellers or high-quality cast impellers.¹⁷ These impellers feature optimized vane counts and a tighter clearance to the water pump divider plate, maximizing volume and pressure.

   

   

• Reduced Cavitation: By engineering the impeller to work precisely with the divider plate, these pumps resist the formation of steam bubbles (cavitation) that can destroy pump efficiency at high RPM.

• Material Options: Builders can choose from high-volume cast iron pumps for a factory appearance or lightweight billet aluminum pumps for reduced frontal mass and superior heat transfer.

   

   

 Electric Water Pumps

For dedicated racing or ultra-high-performance street cars, Meziere Electric Water Pumps offer the ultimate in controlled cooling:

• Eliminate Parasitic Loss: Electric pumps remove the physical drag of the mechanical fan and pump from the engine's accessory drive, freeing up horsepower and torque.

• Constant Flow: They provide a constant, high-volume flow (often 35 to 42 Gallons Per Minute) regardless of engine speed, which is ideal for cooling down between drag passes or managing heat during long idling periods.

• Integrated Design: Meziere pumps bolt directly in place of the stock mechanical pump, offering a clean, lightweight, and extremely efficient cooling solution.

    

By offering a comprehensive selection of pumps and essential conversion kits, Butler Performance provides the expertise and parts needed to ensure any Pontiac V8 remains cool, reliable, and powerful under all operating conditions.