The Flowmaster Flow FX Direct-Fit Muffler is designed for 2020–2025 GM 2500HD and 3500HD trucks with the 6.6L gas engine. This performance muffler provides aggressive to moderate exhaust tone, improves acceleration and towing performance, and maintains factory warranty.

Key Features:
• 3.5-inch mandrel-bent 16-gauge 409 stainless steel tubing maximizes exhaust flow and durability
• Flow FX straight-through muffler delivers deep, aggressive to moderate tone with no interior drone
• Connects directly to the factory tailpipe for a simple and effective upgrade
• Max dyno gains: 7 hp and 5 lb-ft at the rear wheels
• Uses all factory hanger locations for easy at-home installation
• Kit includes all hardware and installation instructions
• Maintains factory warranty
• Covered by Flowmaster’s Lifetime Limited Warranty

This direct-fit muffler is ideal for truck and SUV owners seeking performance improvements, aggressive/moderate sound, and a reliable, stainless steel construction for years of trouble-free service.

Specifications:
• Exhaust Type: Direct-Fit Muffler
• Main Piping Diameter: 3.50"
• Muffler Series: FlowFX
• Muffler Type: Absorption
• Muffler Shape: Oval
• Muffler Material: 409 Stainless Steel
• Muffler Body Dimensions: 10" L × 8" W × 5" H
• Muffler Inlet: 3.5" Center, Slip-Fit
• Muffler Outlet: 3.5" Center, Slip-Fit
• Tailpipe Connection: Factory Tailpipe
• Sound Level: Aggressive / Moderate
• Mount Type: Uses Factory Hangers
• Clamps Included: Yes
• Tip Finish: N/A
• Tubing Material: 409 Stainless Steel
• Overall Length: 34.25"

Fitment 

Compatible Vehicles:
• 2020 GM 2500HD 6.6L Gas Engine
• 2021 GM 2500HD 6.6L Gas Engine
• 2022 GM 2500HD 6.6L Gas Engine
• 2023 GM 2500HD 6.6L Gas Engine
• 2024 GM 2500HD 6.6L Gas Engine
• 2025 GM 2500HD 6.6L Gas Engine
• 2020 GM 3500HD 6.6L Gas Engine
• 2021 GM 3500HD 6.6L Gas Engine
• 2022 GM 3500HD 6.6L Gas Engine
• 2023 GM 3500HD 6.6L Gas Engine
• 2024 GM 3500HD 6.6L Gas Engine
• 2025 GM 3500HD 6.6L Gas Engine

Notes: Fits both 2WD and 4WD models. Maintains factory hanger locations for simple installation. Ideal for performance upgrades with minimal installation effort.