Flowmaster · New

Flowmaster 20-25 GM 2500/3500 6.6L GAS Direct Fit FlowFX Muffler

Name: Flowmaster 20-25 GM 2500/3500 6.6L GAS Direct Fit FlowFX Muffler
Brand: Flowmaster
SKU: flo718155
Price: 479.95 USD

MPN 718155 · Store SKU flo718155

$479.95

IN STOCK1 ready to ship

Supplier stock checked 11/8/2026, 4:09:39 AM UTC. Adding a part does not reserve it.

30-day returns for unopened, unused new parts

Request a return within 30 calendar days after delivery. New parts must be unopened and unused.

Shipping & returns ↗This policy does not limit rights required by law.

Free standard shipping on eligible parts orders of $100 or more. Oversized and freight items excluded. Fitment, taxes, availability and final totals are confirmed before payment.

Product details

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. Fits 2020-2026 GM 2500HD/3500HD 6.6L Gas Engine FFX Direct Fit Muffler Exhaust System, 409 stainless steel Flowmaster Flow FX Direct Fit Muffler

Manufacturer fitment & guides

Check 718155 against the manufacturer’s application information below.

Part-specific notes

California Proposition 65: Y

Manufacturer documents

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