Flowmaster American Thunder Cat-back Exhaust System

2019-2020 GM Silverado/Sierra 1500 (New Body Style) 5.3L engines. (See applications below)

PART# 817853

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Fits 2019-2020 GM Silverado/Sierra 1500 (New Body Style) 5.3L, 2/4 WD Crew/Dbl Cab (except Crew Cab 2WD with 2 Pc Driveshaft and Trucks with Factory Dual Exhaust.)


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 2019-2020 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. Does not fit crew cab 2WD with 2-piece driveshaft, 2019 LD/classic body or trucks with factory dual exhaust tailpipes.


  • 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


California Proposition 65 Chemical Name 1Nickel (metallic)
California Proposition 65 Chemical Name 2Chromium (hexavalent compounds)
California Proposition 65 RequiredYes
Catalytic Converter IncludedNo
Emission Code5
Exhaust SeriesAmerican Thunder
Exit PositionDual Out Rear / Dual Out Side
Heat ShieldNo
Mount TypeUses Factory Hangers
Muffler Body Length (in)13.5
Muffler ColorBlack
Muffler FinishPainted
Muffler Inlet Diameter (in)3
Muffler Inlet LocationCentered
Muffler Material409S Stainless Steel
Muffler Outlet Diameter (in)2.5
Muffler Outlet LocationDual Outlet
Muffler Overall Length (in)19.5
Muffler Part NumberKit Only
Muffler Quantity1
Muffler SeriesSuper 40 Series
Muffler ShapeOval
Muffler TypeReflection
Product TypeExhaust System
Single DualDual
Sound LevelModerate/Aggressive
System TypeCat-back
Tip CutAngle
Tip Diameter (in)3.5
Tip Edge StyleCut
Tip FinishPolished
Tip Length (in)13
Tip LogoEmbossed
Tip Material304 Stainless
Tip Quantity2
Tip ShapeRound
Tubing Diameter (in)2.5
Tubing Material409S Stainless Steel
Part Number817853


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.

Tech Resources

Fits 2019-2020 GM Silverado/Sierra 1500 (New Body Style) 5.3L, 2/4 WD Crew/Dbl Cab (except Crew Cab 2WD with 2 Pc Driveshaft and Trucks with Factory Dual Exhaust.)


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