Flowmaster Flow FX Cat-Back Exhaust SystemThis Flowmaster Flow FX cat back exhaust system for the 2019 2023 GM Silverado Sierra 1500 trucks with the 6. 2L engine and factory dual exhaust, is manufactured using durable 409 stainless steel throughout and features 3. 5 inch to dual 2. 50 inch mandrel bent pipes for better exhaust gas flow, and a Flow FX "straight through" muffler is used for a moderate sound level and maximum performance. Maximum increases on the dyno revealed +26 hp and +39 lb.