Boost the performance of your 2011-2016 GM 6.6L with a high-quality exhaust manifold from Alligator Performance. Our exhaust manifolds are designed to deliver noticeable gains in horsepower, torque and reducing back pressure. Enhance throttle response and unlocking the full potential of your 6.6L Duramax. Choose from a variety of styles, whether you’re looking for increased low-end power with a single-scroll manifold or top-end performance with a twin-scroll design. Discover the perfect match for your GM at Alligator Performance. Further enhance your diesels performance withEngine Upgrades! GM Duramax Fitments: 2011, 2012, 2013, 2014, 2015, 2016 GM 6.6L Duramax.Submodel Fitments: WT, Custom, LT, LTZ, High Country, 1LT, 2LT, Pro, SLE, SLT, AT4, Denali.Some exceptions apply, please see individual product pages for specific fitments.