Gasket - GM LS Throttle Body 105mm

The Gasket - GM LS Throttle Body 105mm (HLY508-24) is a critical sealing component engineered for LS-platform intake manifold builds and throttle body installations. This precision gasket seals the interface between your 105mm throttle body and the intake manifold, preventing vacuum leaks that compromise idle quality, fuel economy, and engine control system stability. Whether you're building a carbureted LS, EFI conversion, or upgrading from factory equipment, a proper gasket seal is non-negotiable for reliable operation.

Manufactured by Holley, a trusted name in LS performance and fuel delivery systems, this gasket is engineered to handle the thermal cycling and positive crankcase ventilation pressures inherent to modern LS engines. The 105mm bore matches OEM and aftermarket throttle bodies, providing a reliable seal without compromising airflow or throttle response. Proper gasket selection prevents the hidden air leaks that cause rough idle, hesitation at part throttle, and nuisance check engine lights—issues that can be maddeningly difficult to diagnose if gasket quality is compromised. At just 0.1 lbs, this lightweight component is designed for a single installation per rebuild cycle.

This gasket is essential for any LS platform builder working with throttle body manifold combinations, including street engines, crate motor installs, and performance swaps into non-LS platforms. Installation is straightforward: position the gasket between the throttle body and manifold mounting surface, ensuring proper seating before torque-down. Always use a fresh gasket during assembly; reusing old gaskets risks compromised seals and the performance issues that follow. For engines running fuel injection with mass air flow or speed-density tuning, a vacuum leak at the throttle body gasket will throw your tune off and cause the ECU to compensate unpredictably.