Rear Main Seal Housing Gasket

The Rear Main Seal Housing Gasket (MPN 12555771) is a critical sealing component engineered for small-block Chevrolet engines. This compressed fiber gasket sits between the rear main seal housing and the engine block, preventing oil leakage at one of the most vulnerable points in your engine assembly. Whether you're rebuilding a classic small-block Chevy, restoring a performance engine, or executing a complete engine overhaul, this OEM Chevrolet Performance gasket ensures a factory-spec seal that protects against costly oil seepage and contamination.

Manufactured from compressed fiber material, this gasket offers superior durability and oil resistance compared to generic alternatives. The compressed fiber construction provides excellent compressibility during installation, allowing it to conform precisely to the mating surfaces of both the housing and engine block. At just 0.05 lbs with compact dimensions of 8.1 x 1.15 x 9.05 inches, this gasket delivers reliable sealing performance without adding weight to your assembly. Chevrolet Performance's engineering ensures this component meets OEM specifications for torque retention and long-term reliability under typical operating conditions.

Mechanics and engine builders trust this gasket for small-block installations across 265, 283, 302, 305, 307, 327, 350, and 400 cubic-inch variants. Installation requires careful preparation of mating surfaces and proper torque sequencing to ensure consistent clamping force and effective sealing. This single-unit gasket is essential during any engine rebuild where the rear main seal housing is disturbed, making it a must-have inventory item for professional and serious amateur engine work. Replace this gasket whenever the rear housing is removed to avoid repeat disassembly and ensure optimal engine longevity.