Description
Overview
The Flowmaster Flow FX Exhaust Muffler Assembly is a direct-fit performance upgrade engineered for the 2020-2026 GM 2500HD and 3500HD trucks equipped with the 6.6L gas engine. Built to help you customize your Chevrolet or GMC truck to your personality, this value-packed muffler system delivers a more aggressive tone, stronger performance, and years of trouble-free service. It fits both 2- and 4-wheel-drive models, making it a versatile choice when you shop for exhaust upgrades that install right at home.
Constructed entirely from 409 stainless steel — including the muffler body, pipe, and tubing — this cat back muffler system is designed to resist corrosion and hold up to the demands of daily driving and towing. The Flow FX series muffler uses a straight-through, absorption-style design that produces great sound and maximum flow with no interior drone, so your car exhaust note stays aggressive on the throttle and comfortable at cruise.
Key Benefits
This performance exhaust routes a 3.50-inch inlet pipe into the 409 stainless Flow FX muffler, then connects to the factory tailpipe for a simple, effective upgrade. Dyno testing shows max gains of 7 horsepower and 5 lb-ft of torque at the rear wheels, translating into better acceleration and improved towing performance. Because the exhaust system uses all the factory hanger locations and OEM-style connections, installation is straightforward and DIY-friendly.
- Direct-fit Flow FX muffler assembly for 2020-2026 GM 2500HD/3500HD with the 6.6L gas engine
- Full 409 stainless steel body, pipe, and tubing for long-lasting durability
- 3.50-inch inlet and outlet diameters with a straight-through, absorption-style design
- Aggressive / moderate sound level with no drone
- Max dyno gains of 7 hp and 5 lb-ft at the rear wheels
- Uses factory hangers; flat band clamps and hardware included
Sound & Design
As a straight-through absorption muffler, the Flow FX delivers the deep, aggressive character truck owners want without sacrificing everyday comfort. The natural finish, oval-profile assembly and center inlet/center outlet configuration keep the flow smooth and the tone clean, giving you a Flowmaster muffler note that stands out from a stock setup while remaining refined enough for the highway.
Fitment & Installation
This cat back exhaust system-style upgrade is engineered to bolt in using all factory hanger locations and connections, then tie into the factory tailpipe. The kit includes flat band clamps and all necessary hardware along with installation instructions, so you can complete the job in your own garage. Fitment covers both 2- and 4-wheel-drive configurations of the 6.6L gas GM 2500HD and 3500HD trucks.
Backed by Flowmaster’s Lifetime Limited Warranty. This product carries a California Proposition 65 warning.
