1/2" Open Phenolic Carburetor Spacer Fits Holley Carb Chevy 4BBL SBC BBC 0.5"

1/2" 4150/4160 Holley Open Phenolic Carburetor Spacer - Black. Made out of phenolic resin and engineered to reduce heat transfer from the intake manifold to the carburetor that provides a denser air/fuel mixutre for increased power and efficiency.