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Manufacturer information. Check the part number and installation requirements for your vehicle.
Supplier details checked 2026-09-23 · Test catalog
Fits 1999-2007* (*Classic body) GM Silverado/Sierra 1500 with either a 4.3L, 4.8L or 5.3L engine. 2/4 Wheel Drive with 143.5 inch wheelbase - Moderate sound
Flowmaster Flow FX Cat-Back Exhaust System
Mandrel-bent 16-gauge 409 stainless steel tubing maximizes exhaust flow with excellent corrosion resistance
Includes complete hardware and factory styled hangers in stock locations for an easy installation
Flow FX "straight-through" performance muffler delivers a deep tone and improved exhaust flow
Large 4.50-inch black ceramic coated stainless steel tips offers an aggressive look
Increases of up to 8 hp and 7 lb/ft of torque over the stock exhaust
System produces a nice rumble with minimal interior resonance
Clears the factory spare tire
Lifetime Limited Warranty
Fits 1999-2007* (*Classic body) GM Silverado/Sierra 1500 with either a 4.3L, 4.8L or 5.3L engine. 2/4 Wheel Drive with 143.5 inch wheelbase
Flowmaster 99-06 GM 1500 V6/V8 FlowFX Cat-Back DOS Exhaust System
9906 GM 1500 V6V8 FFX CB DOS
SYS 99-06 GM 1500 V6
This Flow FX cat-back exhaust system is for 1999-2007* (*Classic body) GM Silverado/Sierra 1500 with either a 4.3L, 4.8L or 5.3L engine and is manufactured using durable 409 stainless steel throughout and features a 3.00-inch inlet pipe leading to a single inlet/dual outlet Flow FX "straight-through" muffler for great sound and maximum performance. The dual 2.50-inch mandrel-bent tailpipes exit out the side at an angle behind the rear wheels directing exhaust away from your boat or travel trailer when towing. The system is finished off with a pair of large 4.50-inch diameter black ceramic coated 304S stainless steel tips, giving your truck a custom look that goes hand in hand with that deep performance Flow FX sound. The system uses all the existing factory hanger locations and includes an additional hanger to install the new left side tailpipe. Includes installation instructions and all necessary hardware for an easy installation that you can do at home. Note: Fits 2 & 4 Wheel Drive with 143.5 inch wheelbase.
SYS 99-06 GM
