Doug Thorley Headers THY-309-C shortie headers deliver the ultimate in performance and gas mileage for your 2002-2012 GM Silverado/Sierra, Suburban, Tahoe/Yukon, Avalanche, Escalade, Denali, Hummer H2. Shortie headers are designed to replace the factory stock exhaust manifolds with a performance component that flows much better than stock. That better exhaust flow produces noticable gains in horsepower and torque output, while increasing fuel efficiency. The headers are manufactured using heavy duty 14GA steel tubing, and super flat 3/8 inch head flanges. They are then silver ceramic coated inside and out, which looks great, drastically reduces under-hood temperatures, and creates a strong barrier to protect the headers from the environment. APPLICATION SPECIFICS: 2002-2012 GM Silverado/Sierra, Suburban, Tahoe/Yukon, Avalanche, Escalade, Denali, Hummer H2, 4.8L, 5.3L, 6.0L, 6.2L, 2/4WD, no EGR fitting.