4.320 MLS Head Gasket .027 - BBC

The 4.320 MLS Head Gasket .027 - BBC from Cometic Gaskets is a precision-engineered sealing component designed for big-block Chevrolet engines demanding maximum reliability and performance. This multi-layer steel (MLS) gasket represents the gold standard for serious engine builders and performance enthusiasts who refuse to compromise on head gasket integrity during high-horsepower builds, race applications, or heavily modified street engines. Whether you're assembling a fresh long-block or refreshing a tired engine, this gasket delivers the seal quality required to contain combustion pressures and coolant circulation safely.

Multi-layer steel construction provides superior sealing surface durability and thermal stability compared to traditional composite gaskets, making the 4.320 MLS Head Gasket .027 - BBC ideal for forced induction, nitrous oxide systems, and high-compression builds that generate extreme cylinder pressures. The .027-inch compressed thickness is precisely engineered to maintain proper combustion chamber volume and ensure accurate ignition timing when used with matching cylinder head deck surfaces. Cometic's proprietary coating technology promotes consistent clamping force distribution across the gasket face, reducing hot-spot failures and preventing coolant migration that can compromise engine longevity during sustained high-rpm operation.

This gasket is essential for BBC (big-block Chevrolet) engine platforms including 396, 427, and 454 variants, and performs exceptionally well in LS-based big-displacement conversions where traditional BBC architecture is modified for modern performance standards. Proper installation requires clean deck surfaces, correct head bolt torque sequencing per manufacturer specifications, and appropriate fastener specification—this gasket demands precision to deliver its full sealing potential. Experienced builders and machine shops across North America specify Cometic MLS gaskets for customer engines where warranty support and repeatability matter most, making it the preferred choice for shops building customer cars or competition engines.