Achieve a reliable seal with the KoiLuvGo Thermostat Housing Gasket. Its innovative design combines a sturdy 1/8-inch aluminum carrier with a molded silicone insert, creating a superior barrier against coolant leaks that outperforms standard gaskets. This durable, reusable gasket requires no sealant and is engineered for compatibility with popular small block and big block engine applications. Replacement for Chevy SBC BBC Engines 265 283 305 327 350 383 396 400 427 454 472 500. Easy to install, it ensures your cooling system maintains proper engine temperature and integrity. A long-lasting solution for preventing leaks between the thermostat housing and water neck.