Dorman 615-300 Lower Intake Manifold Re-engineered by Dorman with heat-resistant molding to reduce both warping and coolant leaks (where applicable) Some manifolds feature a reinforced aluminum coolant crossover to eliminate corrosion and vibration (where applicable) Reinforced EGR and coolant passage walls for increased manifold durability (where applicable) Torque specifications & bolt tightening sequence are provided for easier installation (where applicable)