The GM 12637647 Updated Driver Side Exhaust Manifold for your 2001-2016 GM 6.6L Duramax features a “full bore” unlike the factory exhaust manifold that is “kinked or dented” for additional clearance. The increased flow will “balance” the engine and provide increased spool-up, throttle response and better overall performance. This GM OE part is constructed to the same high quality standards as your factory exhaust manifold.
GM OE Exhaust Manifold
Upgrade On 2001-2010 Duramax Trucks
Because this is the factory manifold that comes on the 2011-2016 LML Duramax it is simply a replacement part for the LML and not an upgrade like the 2001-2010 trucks with the “kinked” exhaust manifold. Exhaust manifold gasket not included.