BBC Gen V/VI Rear Main Seal

The BBC Gen V/VI Rear Main Seal from Chevrolet Performance (part number 6264902) is a precision O-ring engineered to seal the junction between the engine block and crankshaft on big-block Chevrolet V8 engines. This critical component prevents oil leakage from the rear of the engine, maintaining proper lubrication and protecting internal engine components from oil loss during normal operation and extended performance driving.

Specifications are precisely engineered for proper fit and sealing: 0.565-inch inside diameter, 0.77-inch outside diameter, and 0.1-inch thickness. Constructed from durable black rubber, this O-ring is designed to withstand engine temperature cycles and oil exposure inherent to high-performance big-block applications. Chevrolet Performance seals meet OEM specifications and material standards required for reliable long-term performance in both stock and modified engines.

This rear main seal is essential for anyone rebuilding a big-block Chevrolet engine, performing routine maintenance, or addressing oil seepage at the crankshaft. Whether you're restoring a classic muscle car, maintaining a truck engine, or building a performance powerplant, this Chevrolet Performance OEM-equivalent seal ensures proper crankshaft sealing without compromise. Installation requires engine disassembly at the bell housing, making it suitable for experienced DIY builders or professional engine shops.

Rear main seals are wear items that degrade under heat and oil exposure over time. Replacing the seal during any engine rebuild or when oil seepage appears at the rear of the block prevents secondary damage and ensures proper engine longevity. Chevrolet Performance components are engineered to factory specifications, delivering the reliability expected in OEM replacement and rebuild applications.