TBI Flange Gasket

The Holley TBI Flange Gasket (part number 508-11) is a composite throttle body intake manifold gasket engineered for Holley 2-Barrel Pro-Jection fuel injection systems. This gasket seals the critical interface between the throttle body and intake manifold, preventing vacuum leaks and fuel mixture disruption that degrade engine performance and emissions control.

Constructed from composite material, this OE-specification gasket withstands thermal cycling and pressure cycling without degradation across the operating temperature range of carbureted and fuel-injected engines. The 6.75 x 7-inch flange dimensions match factory Holley 2-barrel manifold ports precisely, ensuring correct sealing without excess compression that can warp aluminum surfaces. At 0.1 lbs, the gasket integrates seamlessly into the intake assembly without adding weight or requiring structural reinforcement.

This replacement is essential for engine builders, carburetor technicians, and small-block enthusiasts performing Pro-Jection system installation, maintenance, or restoration. Vacuum leaks at the throttle body-to-manifold interface are a leading cause of stumble during acceleration, high idle, and rough idle conditions in carbureted and early fuel-injected powerplants. A fresh Holley gasket eliminates this common failure point and restores proper air-fuel mixture control.

The composite construction resists fuel contamination, oil seepage, and coolant intrusion better than paper gaskets, making it the preferred choice for long-term reliability in street and classic car applications. Always replace the gasket during any Pro-Jection intake work to avoid re-assembly leaks and unnecessary troubleshooting downrange.