4.125 MLS Head Gasket .060 - SBM

The 4.125 MLS Head Gasket .060 - SBM by Cometic Gaskets is engineered for small-block modified (SBM) engines demanding precision sealing at the cylinder head. This gasket is essential for builders and mechanics performing high-performance engine builds, restorations, or top-end rebuilds where stock gaskets no longer meet compression or boost requirements. The .060-inch thickness positions this gasket in the mid-range for combustion chamber volume adjustments, making it a critical component when combining cylinder head work with block machining.

MLS (Multi-Layer Steel) head gaskets like this Cometic design use layered steel construction with elastomer-coating to withstand elevated cylinder pressures while maintaining a reliable seal across varied surface finishes. The 4.125-inch bore diameter matches small-block applications with precision tolerances, and the .060-inch thickness affects final compression ratio and combustion chamber volume—critical when pairing with ported heads or stroker cranks. Cometic's manufacturing standards ensure repeatable clamp loads and minimal blowby, even under sustained boost or nitrous oxide systems where traditional composite gaskets would fail.

This gasket suits experienced engine builders and performance shops working on street, strip, or off-road small-block platforms—particularly those running carburetor or fuel-injection setups with forced induction or naturally aspirated builds exceeding 400 horsepower. Proper installation requires clean, flat deck surfaces, correct head bolt torque sequences, and application of appropriate gasket sealant per engine manufacturer specifications. The .060 thickness is standard for most small-block configurations; verify your engine's specific requirements and any changes to combustion chamber volume before ordering to ensure optimal compression ratio and detonation margin.