I had a 2006 Ford F - 350 SRW with the 6.0L and a 2009 Dodge Ram 3500 with the 6.7 Cummins and I put complete Banks systems on them. Huge power and never rolled coal. Light to medium brown haze yes but never black soot. When you get black soot it means you have more fuel than can be burned with the amount of air the engine is getting. So basically you are wasting fuel.