The AFE 46-40012 BladeRunner Ductile Iron Exhaust Manifold for your 03-07 Dodge 5.9L Cummins sets a new standard in manifold design. In recent testing, this exhaust manifold outflowed the factory exhaust manifold by up to 23%, improving performance and throttle response. The thick wall (0.25"" vs. 0.15"") T3 flange design increases strength, eliminating warping and cracking prevalent in the factory exhaust manifolds. The matched ports and merged runner design reduces exhaust backpressure, maximizing exhaust flow. Once you install this awesome exhaust manifold, you will feel quicker turbo spool up times, improved throttle response and increased performance. Gaskets Not Included.Â One-Piece Construction: This manifold is constructed of durable cast ductile iron with a reinforcing rib for maximum strength between the port flanges.Â Dual Auxiliary Ports: Two Exhaust Gas Temperature (EGT) probe ports are supplied for easy installation of gauges or testing equipment. Hassle-Free Installation: Â All necessary hardware is included for a hassle-free installation. Features:Â One-Piece DesignÂ Dual Auxiliary PortsÂ CARB EO# D-550-32 Ductile Iron Construction Note: Gaskets and replacement manifold bolts not included. CA Residents: CARB E.O. Number on file - LEGAL for use in California.