340 Chrysler Exhaust Gsk

The Mr. Gasket 340 Chrysler Exhaust Gasket (SKU MRG358, MPN 358) is a high-performance composite exhaust header and manifold gasket engineered specifically for Small Block Mopar engine applications. Designed to seal the critical interface between the exhaust manifold and cylinder head, this gasket maintains combustion integrity and prevents exhaust leakage that can compromise engine efficiency and throttle response.

Built with composite material construction, the gasket features rectangular port dimensions of 1.300 x 1.800 inches and is supplied as a pair—one gasket for each manifold. This composite design delivers superior heat resistance and gasket longevity compared to traditional asbestos alternatives, while maintaining reliable sealing across repeated thermal cycles. The lightweight design (0.25 lbs total) minimizes added weight while providing the durability required in performance and street applications where manifold temperatures frequently exceed 1,000°F.

This gasket is essential for 340 Chrysler engine builds, whether for restoration, performance upgrades, or routine manifold replacement. Proper exhaust sealing prevents unwanted air intrusion that can skew oxygen sensor readings and trigger diagnostic trouble codes. Mr. Gasket's reputation for precision manufacturing ensures correct port alignment and consistent pressure distribution across the sealing surface, reducing the risk of blow-out leaks that can develop from poor fitment or inferior material quality.

The 340 Chrysler engine platform remains popular in classic muscle car restoration and performance street builds, where OEM gasket specifications are either unavailable or prone to early failure. Mr. Gasket's composite gaskets address this need with a modern material solution that outlasts stock designs while maintaining full compatibility with original manifold geometry and bolt patterns.

Installation requires standard manifold removal and surface cleaning to ensure optimal sealing performance. The gasket pair should be installed with correct bolt torque specification for the manifold in use—typically 15–20 ft-lbs for Small Block Mopar applications, though specific torque values should be verified against engine documentation.