Rear Main Seal - SBC GM Aluminum Sprint 400 Main

The Cometic Gaskets Rear Main Seal for SBC GM Aluminum Sprint 400 Main is a precision-engineered 2-piece seal designed specifically for Small Block Chevy engines running aluminum main bearing caps in 400-cubic-inch sprint configurations. This component plays a critical role in preventing oil leakage at the crankshaft's aft end, a common failure point in high-performance and racing applications where engine vibration and sustained RPM loads push standard gaskets to their limits.

Constructed from Viton elastomer, this rear main seal offers superior chemical resistance and thermal stability compared to conventional rubber compounds, making it ideal for engines exposed to synthetic oils, extreme temperatures, and aggressive duty cycles. The 2-piece design allows for installation without complete engine disassembly, reducing labor time while ensuring a factory-quality seal interface. Cometic Gaskets' manufacturing precision ensures proper fit with aluminum sprint blocks, where tolerance stack-up between aluminum and iron components demands tighter specifications than stock cast-iron configurations.

This seal is essential for engine builders, sprint car operators, and Small Block Chevy enthusiasts who require reliable containment in performance-modified 400-cubic-inch applications. Whether rebuilding after a season of competition or upgrading from a failing OEM seal, this Cometic product meets the demands of engines where oil loss directly compromises track performance and engine longevity. The individual seal is sold as a single unit per installation.