SBC Exhaust Gasket Set D-Port LT1/LT4 Gen-II

The SBC Exhaust Gasket Set D-Port LT1/LT4 Gen-II (Part Number 411187) is a precision-engineered exhaust header gasket pair designed for GM's LT-series engine platform. This gasket set seals the critical junction between cylinder head and exhaust manifold, preventing combustion gases from escaping into the engine bay and maintaining exhaust system integrity during high-output operation.

Each gasket measures 1.450 x 1.370 inches with a 0.150-inch thickness and is constructed from graphite composite material—a proven gasket substrate that handles thermal cycling and maintains sealing pressure across repeated heat expansion cycles. The D-port configuration is specific to LT1 and LT4 engine blocks, matching the combustion chamber exit geometry of these Gen-II platforms. Graphite gaskets deliver consistent performance across standard and modified engine builds, resisting blowout even under elevated boost conditions or aggressive cam timing.

This gasket set is essential for engine builders, performance technicians, and LT-series engine owners performing head removal or manifold service. Whether during initial assembly, gasket replacement on a high-mileage engine, or intake/exhaust component upgrades, proper gasket selection prevents air leaks that degrade performance and increase emissions. The pair format covers both sides of the engine, eliminating the need for separate left and right gasket purchases.

LT-series engines (LT1, LT4, and related variants) remain the platform of choice for street performance, racing, and marine applications. Correct gasket specification is non-negotiable for maintaining reliability in these applications, where combustion temperatures and exhaust gas velocity demand durable sealing surfaces.