4.630 MLS Head Gasket .040 - BBC Brodix

The 4.630 MLS Head Gasket .040 - BBC Brodix from Cometic Gaskets is a precision-engineered cylinder head gasket engineered specifically for high-performance big-block Chevy builds using Brodix aluminum cylinder heads. This gasket sits at the critical interface between your cylinder head and engine block, sealing combustion pressure, coolant passages, and oil galleries under extreme operating conditions. Builders and engine shops choose this gasket for naturally aspirated and forced-induction big-block applications where reliability and consistent compression ratios are non-negotiable.

This head gasket features a 4.630-inch bore diameter sized to match Brodix cylinder head ports precisely, eliminating port mismatch that can lead to coolant seepage or hot spots. The multi-layer steel (MLS) construction provides superior durability compared to older solid copper or composite gaskets, allowing it to maintain seal integrity across repeated heat cycles and high boost pressures. At 0.040 inches thick, this gasket thickness directly influences your engine's final compression ratio—a critical consideration when dialing in boost levels, fuel octane requirements, and ignition timing for your specific combination. Cometic's advanced coating technology resists blow-by and prevents deformation under sustained cylinder pressure.

Engine builders working with Brodix aluminum heads in 454, 496, 502, and stroker big-block platforms rely on this gasket for both street and competition engines. The 0.040-inch thickness pairs well with modern CNC-ported Brodix heads and works across carbureted, fuel-injected, turbo, and supercharged configurations. Proper installation requires following Cometic's recommended bolt torque sequences and using quality head fasteners; the gasket must be installed dry without sealant for optimal performance. This is a single gasket—order one per engine build—and represents a core component in any serious big-block Chevy project where port matching and compression control are essential.