Flowmaster 20-25 GM 2500HD 6.6L CCB American Thunder Cat-Back Exhaust System

The Flowmaster® American Thunder® Cat-back exhaust system for the 2020-2026 Chevy Silverado and GMC Sierra 2500HD and 3500HD trucks with the 6.6L gas engine, has a moderate to aggressive sound level inside and outside of the truck, with all of the performance benefits you expect from Flowmaster®. Designed for the Crew Cab, Standard Bed (6.5 ft.) models only, this bolt-on, emissions-legal system features a stainless steel 50 Series HD™ muffler and large dual 3.00-inch 409 stainless steel mandrel-bent tailpipes that can be configured to exit either dual straight out the back, or dual out the sides behind the rear wheels which is best suited for towing applications. The system is finished off with a pair of large 4.00-inch polished 304 stainless steel tips and is covered by our Lifetime Limited Warranty. Designed for an easy fit, this system includes all necessary parts and hardware for installation. Fits 2020-2026 GM 2500HD/3500HD with 6.6L gas engine, Crew Cab/Short Bed, Dual Out Rear/Dual Out Side, Polished Tips - Aggressive to moderate sound Fits 2020-2026 Chevy Silverado/GMC Sierra 2500HD/3500HD trucks with 6.6L gas engine. Crew Cab/6.5ft bed only. Will not fit models with 5th wheel tow hitch installed.

• Uses the Factory Hanger Locations for Easy Installation
• Mandrel-bent 16-gauge Tubing for Maximum Exhaust Flow
• 50 Series HD Muffler with Delta Flow Technology
• 409 Stainless Steel Construction for Long Life
• Multiple Tailpipe Exits Provided in Kit
• Increased Performance and Exhaust Flow
• Large 3.00-inch Dual Tailpipes
• Deep Powerful Exterior Sound
• Lifetime Limited Warranty
• Flowmaster Quality

Upgrade the sound, performance, and appearance of your 2020–2026 Chevrolet Silverado or GMC Sierra 2500HD or 3500HD with the Flowmaster American Thunder Cat-Back Exhaust System, Part Number 817933. Designed for trucks equipped with the 6.6L gas engine, this emissions-legal exhaust system is specifically engineered for Crew Cab models with the 6.5-foot standard bed. It delivers a moderate-to-aggressive interior and exterior sound while improving exhaust flow and providing the performance benefits expected from Flowmaster.
Constructed from durable 409 stainless steel, the system uses mandrel-bent tubing and a 50 Series HD muffler with Delta Flow technology for efficient exhaust flow and a deep, powerful exhaust note. Large dual tailpipes support strong flow and provide flexible installation options, allowing the outlets to exit straight out the rear or behind the rear wheels. The side-exit configuration is especially well suited for towing applications. Polished 304 stainless steel exhaust tips complete the system with a clean, high-quality appearance.
This bolt-on kit is designed to use the factory hanger locations for a straightforward installation and includes the required components and hardware. It is not compatible with trucks equipped with a fifth-wheel tow hitch. The Flowmaster American Thunder system is backed by a Lifetime Limited Warranty and delivers dependable durability for demanding truck use. Please verify vehicle configuration and fitment before installation.

Features:

• Factory hanger locations for straightforward installation

• Mandrel-bent 16-gauge tubing for improved exhaust flow

• 50 Series HD muffler with Delta Flow technology

• Durable 409 stainless steel construction

• Dual rear-exit or side-exit tailpipe configuration

• Large dual 3.00-inch tailpipes

• Polished 304 stainless steel exhaust tips

• Deep, powerful exterior sound with a moderate-to-aggressive tone

• Improved performance and exhaust flow

• Designed for 2020–2026 Chevrolet Silverado and GMC Sierra 2500HD and 3500HD trucks with the 6.6L gas engine

• Fits Crew Cab models with the 6.5-foot standard bed

• Not compatible with trucks equipped with a fifth-wheel tow hitch

• Lifetime Limited Warranty

Fitment:
Chevrolet Silverado 2500 HD Custom 2020
Chevrolet Silverado 2500 HD Custom 2021
Chevrolet Silverado 2500 HD Custom 2022
Chevrolet Silverado 2500 HD Custom 2023
Chevrolet Silverado 2500 HD Custom 2024
Chevrolet Silverado 2500 HD Custom 2025
Chevrolet Silverado 2500 HD Custom 2026
Chevrolet Silverado 2500 HD High Country 2020
Chevrolet Silverado 2500 HD High Country 2021
Chevrolet Silverado 2500 HD High Country 2022
Chevrolet Silverado 2500 HD High Country 2023
Chevrolet Silverado 2500 HD High Country 2024
Chevrolet Silverado 2500 HD High Country 2025
Chevrolet Silverado 2500 HD High Country 2026
Chevrolet Silverado 2500 HD LT 2020
Chevrolet Silverado 2500 HD LT 2021
Chevrolet Silverado 2500 HD LT 2022
Chevrolet Silverado 2500 HD LT 2023
Chevrolet Silverado 2500 HD LT 2024
Chevrolet Silverado 2500 HD LT 2025
Chevrolet Silverado 2500 HD LT 2026
Chevrolet Silverado 2500 HD LTZ 2020
Chevrolet Silverado 2500 HD LTZ 2021
Chevrolet Silverado 2500 HD LTZ 2022
Chevrolet Silverado 2500 HD LTZ 2023
Chevrolet Silverado 2500 HD LTZ 2024
Chevrolet Silverado 2500 HD LTZ 2025
Chevrolet Silverado 2500 HD LTZ 2026
Chevrolet Silverado 2500 HD WT 2020
Chevrolet Silverado 2500 HD WT 2021
Chevrolet Silverado 2500 HD WT 2022
Chevrolet Silverado 2500 HD WT 2023
Chevrolet Silverado 2500 HD WT 2024
Chevrolet Silverado 2500 HD WT 2025
Chevrolet Silverado 2500 HD WT 2026
Chevrolet Silverado 2500 HD ZR2 2024
Chevrolet Silverado 2500 HD ZR2 2025
Chevrolet Silverado 2500 HD ZR2 2026
Chevrolet Silverado 3500 HD High Country 2021
Chevrolet Silverado 3500 HD High Country 2022
Chevrolet Silverado 3500 HD High Country 2023
Chevrolet Silverado 3500 HD High Country 2024
Chevrolet Silverado 3500 HD High Country 2025
Chevrolet Silverado 3500 HD High Country 2026
Chevrolet Silverado 3500 HD LT 2021
Chevrolet Silverado 3500 HD LT 2022
Chevrolet Silverado 3500 HD LT 2023
Chevrolet Silverado 3500 HD LT 2024
Chevrolet Silverado 3500 HD LT 2025
Chevrolet Silverado 3500 HD LT 2026
Chevrolet Silverado 3500 HD LTZ 2021
Chevrolet Silverado 3500 HD LTZ 2022
Chevrolet Silverado 3500 HD LTZ 2023
Chevrolet Silverado 3500 HD LTZ 2024
Chevrolet Silverado 3500 HD LTZ 2025
Chevrolet Silverado 3500 HD LTZ 2026
Chevrolet Silverado 3500 HD WT 2021
Chevrolet Silverado 3500 HD WT 2022
Chevrolet Silverado 3500 HD WT 2023
Chevrolet Silverado 3500 HD WT 2024
Chevrolet Silverado 3500 HD WT 2025
Chevrolet Silverado 3500 HD WT 2026
GMC Sierra 2500 HD AT4 2020
GMC Sierra 2500 HD AT4 2022
GMC Sierra 2500 HD AT4 2023
GMC Sierra 2500 HD AT4 2024
GMC Sierra 2500 HD AT4 2025
GMC Sierra 2500 HD AT4 2026
GMC Sierra 2500 HD AT4X 2024
GMC Sierra 2500 HD AT4X 2025
GMC Sierra 2500 HD AT4X 2026
GMC Sierra 2500 HD Base 2020
GMC Sierra 2500 HD Denali 2020
GMC Sierra 2500 HD Denali 2022
GMC Sierra 2500 HD Denali 2023
GMC Sierra 2500 HD Denali 2024
GMC Sierra 2500 HD Denali 2025
GMC Sierra 2500 HD Denali 2026
GMC Sierra 2500 HD Pro 2023
GMC Sierra 2500 HD Pro 2024
GMC Sierra 2500 HD Pro 2025
GMC Sierra 2500 HD Pro 2026
GMC Sierra 2500 HD SLE 2020
GMC Sierra 2500 HD SLE 2022
GMC Sierra 2500 HD SLE 2023
GMC Sierra 2500 HD SLE 2024
GMC Sierra 2500 HD SLE 2025
GMC Sierra 2500 HD SLE 2026
GMC Sierra 2500 HD SLT 2020
GMC Sierra 2500 HD SLT 2022
GMC Sierra 2500 HD SLT 2023
GMC Sierra 2500 HD SLT 2024
GMC Sierra 2500 HD SLT 2025
GMC Sierra 2500 HD SLT 2026
GMC Sierra 3500 HD AT4 2021
GMC Sierra 3500 HD AT4 2022
GMC Sierra 3500 HD AT4 2023
GMC Sierra 3500 HD AT4 2024
GMC Sierra 3500 HD AT4 2025
GMC Sierra 3500 HD AT4 2026
GMC Sierra 3500 HD Base 2021
GMC Sierra 3500 HD Denali 2021
GMC Sierra 3500 HD Denali 2022
GMC Sierra 3500 HD Denali 2023
GMC Sierra 3500 HD Denali 2024
GMC Sierra 3500 HD Denali 2025
GMC Sierra 3500 HD Denali 2026
GMC Sierra 3500 HD Pro 2023
GMC Sierra 3500 HD Pro 2024
GMC Sierra 3500 HD Pro 2025
GMC Sierra 3500 HD Pro 2026
GMC Sierra 3500 HD SLE 2021
GMC Sierra 3500 HD SLE 2022
GMC Sierra 3500 HD SLE 2023
GMC Sierra 3500 HD SLE 2024
GMC Sierra 3500 HD SLE 2025
GMC Sierra 3500 HD SLE 2026
GMC Sierra 3500 HD SLT 2021
GMC Sierra 3500 HD SLT 2022
GMC Sierra 3500 HD SLT 2023
GMC Sierra 3500 HD SLT 2024
GMC Sierra 3500 HD SLT 2025
GMC Sierra 3500 HD SLT 2026