Improve exhaust flow, reduce EGT and gain power. The driver side exhaust manifold is pinched down to allow for steering shaft clearance. As a result, this manifold only flows 80% of the passenger side. BD Diesel's Full Bore exhaust manifold restores the exhaust flow balance. Made from high-silicon ductile iron, drilled and tapped to except the most popular EGT probes and is a direct bolt-in replacement for the factory manifold.