4.500 MLS Head Gasket .040 - BBM

The Cometic Gaskets 4.500 MLS Head Gasket .040 is a multi-layer steel cylinder head gasket engineered for Mopar B and RB-series engine blocks. This precision component maintains critical compression sealing between the cylinder head and block, where combustion pressures demand absolute reliability. The .040-inch compression thickness and 4.500-inch bore specification are matched to these classic Mopar platforms, ensuring proper gasket crush and thermal conductivity for consistent performance across a wide RPM range.

Multi-layer steel construction provides superior sealing capability compared to single-layer gaskets, particularly under high combustion pressures and elevated engine temperatures. The compressed gasket material expands consistently as engine heat rises, maintaining a secure seal without compression loss. This design approach minimizes blow-by and prevents coolant or oil migration across the gasket face. The .040-inch thickness is engineered to work within the factory deck height specifications of B and RB-series blocks, delivering optimal clamping force when torqued to OEM specifications. Cometic's manufacturing tolerances ensure batch-to-batch consistency, reducing installation variables and improving long-term reliability.

This gasket is essential for engine rebuild projects, restoration work, or replacement maintenance on original-equipment and performance-built Mopar B and RB-series engines. Whether rebuilding a stock 440 Magnum or restoring a high-compression 383, this head gasket delivers the proven sealing performance these engines require. Installation requires careful deck surface preparation, proper torque sequences, and adherence to factory specifications for optimal results. A single gasket is included; confirm your engine's bore diameter and compression thickness before ordering to ensure proper fit.