High Flow (Left) Exhaust Manifold - 01-15 Duramax 6.6L 674-731

Package Contents: Exhaust Manifold, 1 Manifold Gasket and 1 Flange, 3 Studs, 3 Washers

More like a kit than a single part, this Exhaust Manifold includes gaskets and downpipe hardware for easier and more complete installation. Since this part is a direct replacement, the exact fit adds another layer of efficiency and convenience.

The stock manifold was formed with a pinch/crease to allow for steering column clearance that was never needed. This pinched section has 3 of your 4 cylinders on the driver side running at 80% flow and causes an exhaust pressure imbalance and higher EGT's. This high flow manifold flows better than the original drivers side manifold by offering less restriction to match passenger side manifold flow. Greatly increased flow characteristics over the original unit and a great alternative to higher priced after market manifolds.