1in Phenolic 4150 Carb Spacer Open Clover

The 1in Phenolic 4150 Carb Spacer Open Clover from Air Flow Research is an essential component for high-performance carburetor tuning and engine optimization. Designed for serious enthusiasts and professional mechanics building modified engines, this spacer sits between your carburetor and intake manifold to fine-tune air and fuel dynamics. Whether you're upgrading a street rod, race engine, or performance daily driver, a quality carb spacer is critical for maximizing horsepower and throttle response while maintaining reliable cold-start characteristics.

Constructed from phenolic material, this 1-inch spacer provides superior thermal insulation compared to aluminum alternatives, reducing heat transfer from the intake manifold to the carburetor bowl and fuel charge. The 4150 flange pattern ensures universal compatibility with virtually all Holley 4150-style carburetors—the industry standard for street and racing applications. The open clover design optimizes airflow distribution and promotes even mixture delivery across all cylinders, enhancing combustion efficiency and engine responsiveness. At just 0.46 lbs, the lightweight phenolic construction minimizes parasitic weight while delivering the thermal management and flow characteristics serious builders demand.

This spacer is ideal for carbureted engines where intake temperature control directly impacts fuel vaporization, cold-start performance, and part-throttle drivability. Professional engine builders and street performance enthusiasts rely on phenolic spacers to isolate carburetor heat while improving mixture atomization—especially critical in forced-induction or high-compression builds where underhood temperatures run hot. The open clover configuration maintains optimal port velocity and cylinder-to-cylinder distribution, making this Air Flow Research spacer a trusted choice for builds ranging from vintage muscle cars to modern street machines requiring traditional carburetion tuning.