In today’s video, we repurpose old semi-truck exhaust components to custom-fabricate a 7-inch exhaust system for Carter’s Cummins-swapped GMC. The end result is both aggressive in sound and solid in craftsmanship. It is by far that biggest exhaust I've ever seen on a diesel truck. Unfortunately, due to classic Wisconsin weather, we didn’t get much time to drive it — but you’ll still get a great look at the build and the final product.