4.165 MLS Head Gasket .040 - SBC Vortec

The 4.165 MLS Head Gasket .040 - SBC Vortec from Cometic Gaskets is the engineered solution for small-block Chevy and Vortec platform builders who demand reliable sealing under high combustion pressures. Whether you're assembling a stock restoration, a daily-driver rebuild, or a performance-oriented stroker package, this multi-layer steel gasket sits at the critical junction between cylinder head and block—the component responsible for containing combustion forces, managing coolant flow, and maintaining compression integrity throughout the engine's lifespan. Choosing the correct head gasket thickness is fundamental; a .040-inch compression gasket raises the effective compression ratio slightly compared to thinner alternatives, making it ideal for mildly boosted or high-revving naturally aspirated builds where every point of compression matters.

Cometic's multi-layer steel construction delivers superior durability and resealing capability compared to conventional composite or embossed copper designs. The 4.165-inch bore specification precisely matches modern Vortec and late-model small-block casting profiles, ensuring proper coolant jacket coverage and oil passage alignment without compromise. The .040-inch thickness is a measured trade-off: it provides increased gasket material for longevity and improved sealing under load, while the multi-layer steel composition resists blow-out and maintains clamp load retention even after extended heat cycling. This gasket is engineered to work with factory or aftermarket cylinder head bolts and accommodates both OEM and performance-grade torque specifications when properly installed with adequate thread sealant and correct assembly sequences.

Mechanics and engine builders working on Chevrolet 262, 305, 327, 350, and 400 cubic-inch small-blocks—as well as Vortec-head platforms—rely on this gasket for both stock rebuilds and modified applications. Installation requires careful head surface preparation, including decking and honing if the block has been previously machined, and strict adherence to head bolt torque specifications in the correct sequence. The gasket's compatibility with both cast-iron and aluminum cylinder heads, combined with its performance reputation, makes it an industry standard for professional shops and dedicated enthusiasts alike. Always verify your cylinder head bore diameter and gasket thickness against your engine's specifications before purchase to guarantee proper fit and optimal sealing performance.