Makes larger chargers more Drivable . Improves Horsepower and Widens Powerband . Excellent Fit & Finish . Ships With Stainless Steel mounting Hardware and Brass 1/8 & 1/4 NPT Plugs . Increased Economy When Installed W/Same Mods . Our Stainless Diesel 2nd gen 24v &12v Cummins exaust manifold was cast with a Stainless steel moon metal mix made for Extreme High Heat cycling . The manifolds are built with 3/4+ inch thick center section with room for Extra porting . Thick wall castings for Great Thermal control . The most superior thermal energy retention for Faster spool up Accelerations . The Super Smooth inside runner sizing is 1.650 inchs all the way to the center outlet for Extreme high flow. Proven smooth single piece cast design , has no steps that block flow in the middle like the old style 2 & 3 piece iron manifolds. The old style 2 & 3 piece iron manifolds are built with steps in the runners causing Inefficient Turbulent Air Flow Inside. Ever wonder why your stock one piece spools better?