4.340 MLS Head Gasket .040 - 426 Hemi

The 4.340 MLS Head Gasket .040 - 426 Hemi from Cometic Gaskets is engineered for serious big-block Mopar builds where reliability and sealed compression matter. This multi-layer steel gasket is designed specifically for the legendary 426 Hemi platform, addressing the demanding sealing requirements of high-displacement, high-boost applications. Whether you're rebuilding a stock engine or pushing aggressive horsepower numbers, a quality head gasket is non-negotiable—it's the critical barrier between your combustion chamber and coolant passages.

Cometic's MLS (multi-layer steel) construction provides superior sealing compared to traditional composite gaskets, especially under high cylinder pressure and temperature cycling. The .040-inch thickness is precision-engineered to work with the 426 Hemi's original deck height and combustion chamber geometry, ensuring proper quench and bore alignment. The 4.340-inch bore diameter matches the Hemi's oversized cylinder openings, and the gasket's design minimizes blow-by, prevents coolant intrusion, and maintains seal integrity across thousands of heat cycles—critical for both street and race applications.

Mechanics and engine builders restoring or modifying 426 Hemi engines—from classic muscle cars to modern restomod projects—rely on Cometic's precision gaskets to eliminate guesswork during reassembly. This gasket is ideal for high-performance applications, ensuring that the engine operates efficiently and reliably under demanding conditions. With its robust design, it supports the longevity and performance of your engine build.