The T1XX platform made its way to GM's HD series trucks for the 2020 model year. With it came major upgrades inside, outside, and most importantly, under the hood. The base engine became a 6.6L LT-based V8 producing 401 horsepower. The 6.6L L5P Duramax is the line-topping diesel and provides 910 lb/ft of torque in stock form. No matter how you put your HD truck to use, we have the parts to make it perform better.

Holley is home to some of the top-performance exhaust brands in the world. Brands like Flowmaster, Hooker BlackHeart, Hooker Classic, Flowtech, APR, Dinan, and Flowmonster combine to cover thousands of applications and a variety of budgets. Whether you are putting a full stainless steel exhaust on your late-model muscle car or if your rat rod needs a set of Lakester headers, Holley’s exhaust brands have you covered.