Phenolic 1/2in 4 Hole

The Phenolic 1/2in 4 Hole carburetor spacer from MOROSO is engineered for engine builders and performance enthusiasts who demand thermal isolation and precise carburetor tuning. This 0.5-inch thick spacer sits between your carburetor and intake manifold, addressing one of the most overlooked variables in carb setup: heat transfer from the engine block to the fuel charge. By reducing fuel vaporization in the bowl and increasing mixture density entering the engine, a quality spacer like this directly improves cold-start behavior, throttle response, and fuel economy across a wide RPM range.

Constructed from phenolic material—a thermoset polymer composite—the Phenolic 1/2in 4 Hole features superior insulating properties compared to aluminum or cast iron spacers. The 1.750-inch bore diameter and square-bore configuration ensure compatibility with popular street and strip carburetors, while the four-hole pattern secures cleanly to both manifold and carb base without binding. Phenolic's low thermal conductivity keeps intake charge temperature stable, preventing heat soak that causes lean stumbles and hesitation during transient throttle movements. The natural finish requires no coating, and the spacer's compact 0.53-pound weight adds negligible inertia to your fuel system.

This spacer is ideal for small-block and big-block Chevy applications, as well as Ford and Mopar platforms running Holley, Edelbrock, or Demon four-barrel carburetors. Installation is straightforward: remove your carb, unbolt the old spacer (if present), and torque the phenolic unit in place using a standard gasket seal. Carburetor spacers are essential for any engine modified with higher compression, aggressive cam timing, or forced induction, where fuel atomization and intake charge cooling become critical to detonation control and driveability. Verify four-hole manifold compatibility before purchase.