Whether you're replacing or upgrading your manifolds, aFe POWER delivers with an all-in-one, bolt-on kit for your 2011 - 2015 GM Diesel Truck with the V8-6.6L (td) LML engine. These hand crafted tubular style headers are constructed out of brush finished, mandrel bent, heavy duty gauge .120 wall, 304 stainless steel tubing. Also featured are; 2" mandrel-bent 304 stainless steel up-pipes, with heavy duty 4" flex tubes, and a 3" 304 stainless steel down-pipe with factory style machined flanges. Tube lengths and mitered collectors are optimized for true pulse control technology which improves flow and performance across the power band. This system is a direct bolt-on installation which requires no cutting or drilling. High quality hardware is included within this kit to ensure hassle-free installation.