4.040 MLS Head Gasket .040 - SBM

The 4.040 MLS Head Gasket .040 - SBM from Cometic Gaskets is engineered for serious engine builders and performance enthusiasts who demand reliability in high-horsepower small-block applications. This multi-layer steel (MLS) gasket represents the modern standard for sealing cylinder head interfaces where traditional composite gaskets fall short. Whether you're rebuilding a stock engine, tuning a street machine, or prepping a competition powerplant, this gasket delivers the consistent clamping load retention and thermal stability required to prevent blow-by, coolant seepage, and combustion chamber leakage.

MLS gasket technology uses multiple layers of spring steel and elastomer coatings to maintain a dynamic seal across varying engine conditions—critical when boost, temperature swings, or cylinder pressure spikes challenge traditional designs. The .040-inch thickness specification allows precise compression ratio management and fits within standard small-block envelope specifications. The 4.040-inch bore diameter is specifically designed for small-block Mopar applications, ensuring compatibility with these engine platforms.

Cometic's proprietary facing compounds resist combustion erosion and maintain gasket compliance even after hundreds of heat cycles, ensuring your gasket won't weep at the critical fire-ring or water passages where premature failure typically begins. This gasket suits small-block applications ranging from naturally aspirated street builds to supercharged and turbocharged engines operating under demanding conditions.