Description
Overview
The Flowmaster Flow FX Cat-Back Exhaust System is a complete bolt-on upgrade engineered to unlock better flow, add power, and give your GM 1500 a genuinely aggressive-yet-livable exhaust note. Designed for 1999-2006 GM 1500 trucks (including the 2007 1500 Classic) equipped with the 4.3, 4.8, or 5.3-liter engine in Crew Cab 5.5′ bed and Extra Cab 6.5′ bed configurations, this system replaces the restrictive factory piping with performance-minded hardware from the cat back to the tips.
Built for the long haul, the entire system is manufactured from durable 409 stainless steel and uses 3.00-inch to dual 2.50-inch mandrel-bent pipes. Mandrel bending keeps the pipe diameter consistent through every bend, promoting smoother exhaust gas flow so the engine can breathe more freely. On the dyno, this translated to maximum gains of +14 horsepower and +13 lb-ft of torque at the rear wheels.
Sound & Performance
At the heart of the kit is a Flow FX “straight-through” muffler, tuned for a moderate to mild interior tone while delivering an aggressive presence when you get on the throttle. It measures 20.00 inches overall with a center inlet and dual 2.50-inch outlets, so you get the deep, purposeful character you want without excessive drone during everyday driving. The muffler is included in the kit and finished in silver to match the piping.
Style & Exit
This dual tailpipe system exits out the same side, positioned in front of the rear wheel on the passenger side, and finishes with dual 4.00-inch black ceramic tips featuring a laser-etched logo for a custom, finished look that stands out.
Fitment & Installation
The system is a true bolt-on. It uses all the existing factory hanger locations and includes installation instructions plus all necessary hardware, making it an at-home install for most enthusiasts with basic tools. It is also CARB (California) compliant, carrying Emission Code 5.
- Fits 1999-2006 GM 1500 (and 2007 1500 Classic) with 4.3L, 4.8L, or 5.3L engines — Crew Cab 5.5′ bed and Extra Cab 6.5′ bed only
- Constructed from durable 409 stainless steel throughout
- 3.00-inch to dual 2.50-inch mandrel-bent pipes for improved flow
- Flow FX straight-through muffler for a moderate-to-mild yet aggressive tone
- Dyno-proven gains up to +14 hp and +13 lb-ft at the rear wheels
- Dual 4.00-inch black ceramic tips with laser-etched logo
- Same-side exit, in front of the passenger-side rear wheel
- Uses factory hangers; includes hardware and instructions for easy install
- CARB compliant and backed by Flowmaster’s Lifetime Limited Warranty
Whether you’re after more power, a better sound, or a cleaner rear-end appearance, the Flow FX cat-back delivers all three in one durable, easy-to-install package.
