Collector Gasket

The Hedman Collector Gasket (Part No. 27420) is a purpose-built exhaust manifold seal designed for high-temperature engine applications. Measuring 3 inches in diameter with a 6-bolt pattern, this gasket features a 0.063-inch thickness and steel core laminate construction—proven specifications that maintain pressure integrity under the thermal stress of sustained engine operation. This is a pair set, providing coverage for dual-outlet or dual-manifold configurations common in performance and heavy-duty engine builds.

The steel core laminate design is critical for longevity in collector gasket applications. Unlike soft gasket materials, the laminated construction resists blow-by and thermal cycling fatigue—essential when managing exhaust temps that routinely exceed 1,000°F. The 0.063-inch thickness balances sealing force with surface flatness requirements, allowing even clamp pressure across the six bolt holes. At 0.08 lbs per pair, the gasket adds negligible weight while delivering reliable performance across thousands of engine cycles.

This gasket serves mechanics, fabricators, and engine builders working on custom headers, turbo setups, and manifold-to-collector transitions where stock sealing has failed or where precise fitment is required. The 3-inch diameter and six-bolt standard fit a wide range of small-block and mid-range engine platforms. Hedman's gasket specification ensures repeatability—critical when baseline engine diagnostics depend on eliminating exhaust leaks as a variable.

Collector gaskets are often overlooked in engine assembly, but failure here causes catastrophic performance loss: exhaust scavenging is compromised, EGT readings become unreliable, and unburned gases escape before reaching the secondary exhaust stage. The Hedman 27420 pair eliminates that weak link at the critical manifold-to-collector interface, making it essential hardware for any serious engine build.