MUFF 20-26 GM 2500/3

Flowmaster's® Flow FX Direct-Fit Muffler exhaust system for the 2020-2026 GM 2500HD and 3500HD trucks with the 6.6L gas engines gives you a great value packed way to help you customize your GM truck to your personality. This performance muffler system fits both 2/4 Wheel drive models and is manufactured from 409 stainless steel for years of trouble-free service and performance. Features include a 3.50-inch inlet pipe leading into a 409 stainless steel Flow FX series "straight-through" muffler for great sound and maximum performance and no drone. The muffler then connects to the factory tailpipe for a simple and effective performance upgrade. Max dyno gains of 7 hp and 5 lb-ft at the rear wheels. This results in better acceleration and towing performance. The system uses all the factory hanger locations and connections for an easy installation that you can do at home. Kits include installation instructions and all necessary hardware. Backed by Flowmaster's Lifetime Limited Warranty.

Additional Information

Fits 20-26 GM 2500HD/3500HD 6.6L Gas Engine FFX Direct Fit Muffler Exhaust System, 409 stainless steel

• 3.5-inch mandrel bent 16-gauge 409 stainless steel tubing maximizes exhaust flow and improves durability
• A tuned Flow FX style muffler delivers a deep, aggressive to moderate performance tone and improves exhaust flow with no drone
• Kit includes complete hardware and factory styled hangers in the stock locations for an easy installation
• Lifetime Limited Warranty
• Maintains factory warranty
• Max increases of up to 7 hp and 5 lb-ft over the stock exhaust at the wheels
• Tuned performance muffler eliminates interior drone

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Product Downloads

#	Document Type	Download
1.	Installation Instructions

Installation guides, warranty details, and other supporting documents are provided by the supplier. In some cases, these files may originate from regions outside your locale, meaning instructions, warranty procedures, and images may not fully align with your specific vehicle or region (e.g., LHD vs. RHD differences, return policies, etc.). If you need clarification, please contact a StreetFX support agent.

Reference Information