Dorman 674-391 Exhaust Manifold - Left

Durable Cast Iron Exhaust Manifold for Chevrolet and GMC Trucks

The Dorman 674-391 exhaust manifold is engineered to provide reliable exhaust flow for Chevrolet and GMC heavy-duty trucks. Designed with a natural cast iron finish and square port shape, this manifold ensures a precise fit and long-lasting performance for models like the Chevrolet C2500 and GMC Savana 3500.

• Constructed from durable cast iron for strength and heat resistance
• Natural color finish with a square port shape for optimal exhaust flow
• Includes mounting hardware: 3 studs, 3 nuts, and 1 manifold gasket
• Comes with a heat shield to protect surrounding components
• Compatible with Chevrolet and GMC models including C2500, K2500 Suburban, and Express 3500

Product Details and Specifications

The Dorman 674-391 exhaust manifold is made from cast iron, a material known for its durability and ability to withstand high temperatures generated by engine exhaust gases. The natural finish maintains the integrity of the material without additional coatings. Featuring a square port shape, this manifold matches the exhaust ports on compatible Chevrolet and GMC engines, ensuring a secure and efficient seal. The package includes all necessary mounting hardware such as studs, nuts, and a gasket, simplifying installation. Additionally, a heat shield is included to reduce heat transfer to nearby engine components, helping maintain overall engine bay temperature control.

Compatible Vehicles and Applications

This exhaust manifold is designed specifically for use with the following Chevrolet and GMC models:

• Chevrolet C2500 and C2500 Suburban
• Chevrolet C3500
• Chevrolet Express 3500
• GMC K2500 and K2500 Suburban
• GMC K3500
• GMC P30
• GMC Savana 3500

Common Issues Addressed by This Exhaust Manifold

• Exhaust leaks caused by cracked or warped manifolds
• Reduced engine performance due to poor exhaust flow
• Excessive engine bay heat damaging nearby components
• Failed or missing mounting hardware leading to improper sealing
• Corrosion or wear from prolonged use of original manifold

Installation Notes and Tips

When installing the Dorman 674-391 exhaust manifold, ensure all old gasket material is thoroughly cleaned from the mounting surface to prevent leaks. Use the included studs, nuts, and gasket for a secure fit. Torque the mounting hardware to manufacturer specifications to avoid warping the cast iron manifold. The included heat shield should be properly positioned to protect adjacent components from heat exposure. It is recommended to inspect related exhaust system components during installation for any signs of wear or damage.

Quality Assurance and Warranty

Dorman exhaust manifolds are manufactured to meet or exceed OEM standards for fit and function. The 674-391 part is made from cast iron to provide durability and resistance to heat and corrosion. This product includes all necessary hardware and a gasket to ensure proper installation. While specific warranty details may vary, Dorman typically offers a limited warranty covering defects in material and workmanship. Refer to the product documentation for exact warranty terms.