Flowmaster® (19-21) Silverado/Sierra 409SS American Thunder Cat-Back System (Crew/Double Cab)

  • Sale
  • Regular price $840.95

Compatible: (5.3L)

2019 - 2021 Chevy Silverado (NEW BODY STYLE)

2019 - 2021 GMC Sierra  (NEW BODY STYLE)


Does not fit crew cab 2WD with 2-piece driveshaft, 2019 LD/classic body or trucks with factory dual exhaust tailpipes.

This part is legal for sale or use on Emissions Controlled Vehicles, Uncontrolled (Non-Emissions Controlled) Vehicles, and Racing Use Only Vehicles because it does not affect vehicle emissions and is not covered by emissions regulations.






This Flowmaster® American Thunder® Cat-back exhaust system is perfect for the person looking for deep, powerful sound outside the vehicle with a little growl inside the cab. This emissions-legal system is for 2WD & 4WD 2019-2021 GM 1500 trucks (new body style) with the 5.3L engine and factory single exhaust. System features include full stainless steel construction, a single in/dual outlet Super 40® Series muffler and mandrel-bent dual 2.50-inch stainless steel tailpipes for maximum performance and a deep sound. This bolt-on system utilizes the factory hanger locations and includes your choice of tailpipe exits, either dual out the rear exiting under the bumper, or dual out the side behind the rear wheels to help prevent blowing exhaust on your boat or trailer when towing. The system is finished off with a pair of large 3.50-inch double wall polished 304 stainless steel tips. Designed for a perfect fit, the system includes installation instructions and all the necessary hardware for an easy at home installation. Note: Fits 2/4 wheel drive Crew cab and double cab models.


  • Large 3.50 inch Polished 304 Stainless Tips
  • Uses the Factory Hanger Locations
  • Deep, Powerful Performance Tone
  • Full Stainless Steel Construction
  • Clears Factory Spare Tire
  • Lifetime Limited Warranty
  • Mandrel-bent Tubing
  • Easy Installation

Brand Flowmaster
Catalytic Converter Included No
Emission Code 5
Exhaust Series American Thunder
Exit Position Dual Out Rear / Dual Out Side
Heat Shield No
Material 409 Stainless Steel
Mount Type Uses Factory Hangers
Muffler Body Length (in) 13.5
Muffler Color Black
Muffler Finish Painted
Muffler Inlet Diameter (in) 3
Muffler Inlet Location Centered
Muffler Material 409S Stainless Steel
Muffler Outlet Diameter (in) 2.5
Muffler Outlet Location Dual Outlet
Muffler Overall Length (in) 19.5
Muffler Part Number Kit Only
Muffler Quantity 1
Muffler Series Super 40 Series
Muffler Shape Oval
Muffler Type Reflection
Product Type Exhaust System
Single Dual Dual
Sound Level Aggressive / Moderate
System Type Cat-back
Tip Cut Angle
Tip Diameter (in) 3.5
Tip Edge Style Cut
Tip Finish Polished
Tip Length (in) 13
Tip Logo Embossed
Tip Material 304 Stainless
Tip Quantity 2
Tip Shape Round
Tubing Diameter (in) 2.5
Tubing Material 409S Stainless Steel
California Proposition 65 Chemical Name Chromium (hexavalent compounds)
Nickel (Metallic)
California Proposition 65 Chemical Name 1 Nickel (metallic)
California Proposition 65 Chemical Name 2 Chromium (hexavalent compounds)
California Proposition 65 Required Yes
Part Number 817853



Install Guide: