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Manufacturer information. Check the part number and installation requirements for your vehicle.
Supplier details checked 2026-09-23 · Test catalog
2001-2006 (2007 Classic) Chevrolet Silverado, GMC Sierra 2500HD/3500HD with 6.0L or 8.1L engine with dual inlet muffler. Stainless Steel. - Aggressive sound
Flowmaster American Thunder Cat-back Exhaust System
3.50-inch Mandrel-bent 16-gauge Stainless Steel Tubing
Includes Hangers and Hardware for an Easy Installation
Large 4.00-inch Polished 304 Stainless Steel Tip
Moderately Aggressive Exterior Exhaust Tone
Connects After Factory Catalytic Converter
Uses the Factory Hanger Locations
Quick and Easy Installation
Lifetime Limited Warranty
Fits 2001-2006 (2007 Classic) Chevrolet Silverado and GMC Sierra 2500 3/4 Ton and 1 Ton HD truck with 6.0L or 8.1L engine with dual inlet muffler, fits 2/4 wheel drive models with extended cab or crew cab.
Flowmaster 01-04 GM 2500HD/3500HD American Thunder SS Cat-Back Exhaust System
0104 GM 2500HD3500HD AMT SOS 409S
SYS 01-04 GM 2500HD/
For the person who wants a subtle custom appearance with all the benefits that a Flowmaster Cat-back exhaust system provides. This American Thunder system for the 2001-2006 (2007 Classic) Chevrolet Silverado, GMC Sierra 2500HD/3500HD with 6.0L or 8.1L engine with dual inlet muffler, delivers a moderate interior tone with a deep powerful exterior tone and is suited to the enthusiast who wants their performance to be heard. The system attaches to the back of the catalytic converter with a dual inlet 50 Series Big Block muffler for a deep powerful sound without being obnoxious. Includes a large custom formed aluminum heat shield with stainless clamps and easily attaches directly to the muffler body. The custom bent 3.50-inch 409 stainless steel tailpipe uses the factory hanger locations for an easy installation and exits out behind the right side rear wheel which is ideal for towing. The tailpipe is finished off with a large 4.00-inch polished 304 stainless steel tip embossed with the Flowmaster logo. Like all Flowmaster systems, the benefits include improved throttle response, power and mileage. Designed for an easy fit, these systems include all necessary parts, hardware and easy to follow instructions for a trouble free installation. Covered by Flowmaster's Lifetime Limited Warranty.
SYS 01-04 GM
