4.200 MLS Head Gasket .027 - SBC

The 4.200 MLS Head Gasket .027 - SBC from Cometic Gaskets is a precision-engineered sealing component designed for small-block Chevy engines requiring reliable head-to-block compression integrity. This multi-layer steel gasket serves engine builders, mechanics, and performance enthusiasts who demand consistent bore sealing across rebuild cycles, street applications, and mild-to-moderate boost scenarios. The .027-inch compressed thickness represents a critical dimension that maintains proper combustion chamber volume and valve train geometry, making it essential for anyone restoring or modifying a SBC platform.

Cometic's multi-layer steel (MLS) construction utilizes stainless steel facings and elastomer core layers to distribute clamping load evenly across the gasket surface, preventing localized hot-spot leaks that plague inferior composite designs. The 4.200-inch bore diameter specification ensures a precision fit on standard small-block Chevy cylinder heads, accommodating both stock and aftermarket head castings with port volumes typically ranging from 64cc to 76cc. MLS gaskets excel under thermal cycling and vibration because the steel layers resist permanent deformation, unlike conventional asbestos or graphite gaskets that compress and relax over time, leading to gradual coolant or oil weeping.

Technicians rebuilding carbureted, fuel-injected, or forced-induction small-block engines benefit most from this gasket's durability and longevity, particularly in high-mileage restorations where compression retention matters for peak engine efficiency. Installation requires proper head bolt torque sequencing and clean mating surfaces free of old gasket material—following Chevrolet's factory bolt pattern and Cometic's recommended clamp load ensures maximum sealing life. Whether you're assembling a 355ci stroker, refreshing an original 350, or preparing a turbo-charged platform, this .027-inch MLS gasket delivers the seal integrity and dimensional stability that separate professional rebuilds from temporary fixes.