The aFe Large Bore-HD 5 IN 409 SS DPF-Back Exhaust System (part 49-44125-P) replaces the stock section behind the diesel particulate filter on the 6.6L Duramax L5P turbo V8. It is built from 5-inch mandrel-bent 409 stainless steel tubing and finished with a 6-inch intercooled clamp-on tip in polished 304 stainless. The manufacturer describes the seams as 100% MIG-welded, which it presents as the basis for the system's strength and durability.
Owners who want a more aggressive exhaust note and a stainless build than a mild-steel or budget aftermarket section offers will get a durable, corrosion-resistant option. The 409 stainless construction is a practical choice for trucks driven in road-salt regions, and the polished tip gives an intercooled look that stock hardware does not provide. Enthusiasts searching for an L5P DPF-back upgrade, a 5 inch 409 stainless exhaust, or a polished intercooled exhaust tip are looking for this exact layout.
Fitment is the first detail to verify. The product title references 2020-2021 GM trucks, while other listings cover 2020-2023 Duramax Double and Crew Cab models, and cab, bed, and drivetrain variations matter. The system uses factory-style flanges and hangers and includes all necessary hardware, which keeps the install closer to a direct replacement. Confirm your exact application with the manufacturer before ordering.
Coverage details vary between sources. The product title lists 2020-2021 GM trucks, while other listings include 2020-2023 Duramax Double and Crew Cab models. Confirm your exact truck, including cab and bed length, with the manufacturer before ordering.
The manufacturer states that all necessary hardware is included and that the tip is a 6-inch intercooled clamp-on design. The polished finish is identified by the -P suffix in the part number.
The manufacturer offers a black-tip version of this system under part number 49-44125-B, with the same 5-inch 409 stainless tubing.
The system is designed around factory-style flanges and hangers, and the manufacturer includes all necessary hardware, so the job is a direct replacement of the stock DPF-back section. I could not locate the manufacturer's install sheet during research, so I cannot confirm difficulty level, torque specifications, or a required tool list. Let the exhaust cool fully before starting, and compare every pipe, hanger, and flange against the factory parts before cutting or removing anything.
