Benifits of the "Full Bore" Manifold Flows 20% more than factory manifold | With the stock manifold only 3 cylinders operate at 80% capacity & load others down | No access to measure exhaust temperature | Flow matches the passenger side manifold and balances the engines exhaust pressure | Maintains consistent exhaust pressure and temperature on both sides of the engine | Contains Exhaust temperature probe port.

BD “Full Bore” Exhaust Manifold Improve exhaust flow, reduce exhaust gas temperature (EGT) and realize greater power gains with the new “Full Bore” driver’s side exhaust manifold for the ’01-’07 GM Duramax. You may not know it, but the factory driver’s side manifold is pinched down to allow clearance for the steering shaft, which actually isn’t required. As a result, this manifold flows 80% of the passenger side manifold. The BD Full Bore exhaust manifold restores exhaust flow to match the passenger side, and is a direct, bolt-in replacement for the factory part (GM gasket required). The BD Full Bore manifold is made from high-silicon ductile iron to resist cracking from high temperature and vibration, and is even tapped to accept the most popular EGT probes