Thermostat Housings/Water Necks

The Billet Aluminum Advantage

The primary reason for upgrading to a billet aluminum thermostat housing is eliminating the common sealing issues associated with stock and generic aftermarket parts.

• O-Ring Seal Technology: Unlike factory housings that rely on a paper gasket and often require messy RTV silicone to achieve a leak-free seal, the premium billet housings offered by Butler Performance are typically O-ring sealed.⁴

   

   

  • The CNC-machined base flange ensures a perfectly flat and smooth surface.⁵

     

     

  • The included O-ring provides a durable, leak-proof seal that can be disassembled and reassembled repeatedly without requiring new gaskets or sealant.⁶

     

     

• Corrosion Resistance: Cast iron and cheap stamped steel housings are susceptible to rust and pitting, which compromises the sealing surface. Billet aluminum (often $6061\text{-T}6$ aluminum) is corrosion-resistant, maintaining a clean, flat flange for the life of the engine.

• Superior Aesthetics: These housings are CNC machined for a clean, precision appearance, often available in polished, chrome, or anodized black finishes.⁷ This provides a clean, professional touch to any high-end Pontiac engine bay.

   

   

The Critical Swivel Feature

One of the most valuable features of the high-performance thermostat housings sold by Butler Performance is the ⁸$360^\circ$ adjustable swivel neck.⁹

The upper radiator hose connection on a classic Pontiac V8 can be challenging to route, particularly when dealing with non-factory radiators, serpentine belt conversions, or clearance issues created by aftermarket air intakes or other accessories.

• Hose Routing Flexibility: The swivel feature allows the user to rotate the upper radiator hose outlet 360 to align the hose perfectly with the radiator inlet.¹¹ This prevents kinking the hose, eliminates stress on the connection points, and provides the cleanest possible hose routing path.

   

   

• Universal Fit: This swivel design makes the housing nearly universal for all Pontiac V8 applications (326, 350, 389, 400, 421, 428, 455 excluding some Tri-Power configurations), greatly simplifying inventory and ensuring the right fit every time.¹³

   

   

AN Fitting Options for Race Applications

For serious race builders utilizing custom aluminum radiators and braided stainless steel or nylon AN lines instead of traditional rubber hoses, Butler Performance also stocks specialized thermostat housings designed for this application.

• AN Hose Connect Housings: These specialized housings come equipped with an AN fitting port (such as -16AN or -20AN), allowing the builder to connect the radiator line directly to the water neck using AN fittings.¹⁶ This provides a maximum-flow, racing-grade connection that is essential for ultra-high-horsepower builds and extreme thermal management.

   

   

Whether restoring a factory look or building a 700hp stroker, upgrading the thermostat housing to a billet, O-ring sealed unit is a simple, effective, and essential step in building a reliable and clean Pontiac cooling system.