4.165 MLS Head Gasket .066- SBC

The 4.165 MLS Head Gasket .066- SBC is a precision-engineered multi-layer steel cylinder head gasket designed specifically for small block Chevrolet engines. Built for enthusiasts and professional mechanics rebuilding or refreshing classic SBC powerplants, this gasket seals the critical interface between the cylinder head and engine block—a joint that experiences extreme pressure, heat, and combustion forces. Proper head gasket selection is fundamental to engine reliability; a gasket failure can compromise compression, allow coolant intrusion, and result in catastrophic engine damage.

This multi-layer steel (MLS) construction delivers superior durability and conformability compared to traditional composite gaskets, allowing the gasket to maintain a consistent seal across the mating surfaces throughout the engine's operating cycle. The 4.165-inch bore specification matches the cylinder opening diameter of many small block Chevy heads, while the 0.066-inch compression thickness is carefully calculated to achieve the correct deck height and compression ratio for your specific engine combination. MLS gaskets excel at handling thermal expansion and contraction cycles, resisting blow-by, and maintaining sealing integrity even under high-boost or nitrous applications—making them the preferred choice for serious engine builders.

This head gasket is ideal for anyone performing a complete small block Chevy overhaul, whether assembling a street engine, competition build, or restoration project. Proper installation requires clean, flat mating surfaces, correct bolt torque sequence, and use of the manufacturer's recommended head bolt specifications—critical steps that ensure the gasket performs as engineered. Compatible with small block Chevy platforms from the 265 through 400 cubic inch variants, this gasket works across a wide range of cylinder head designs and aftermarket modifications, making it a reliable choice for both stock and modified applications.