American Thunder™ 409 SS Axle-Back Exhaust System with Split Rear Exit (817751) by Flowmaster®. Exhaust System Type: Axle-Back. Exhaust Tubing Material: 409 SS. Main Tubing Diameter: 2.5". Exhaust System Sound: Moderate. American Thunder exhaust system is perfect for the person looking for a moderately aggressive sound level outside of the car, while maintaining a mild sound level inside, with all of the performance benefits that you would expect from Flowmaster. American Thunder gives you the classic sound of a Flowmaster chambered exhaust, which is the classic sound of classic American big performance engines. This is a system that gives the most sedate vehicle a performance rumble.
Flowmaster is a manufacturer of performance exhaust systems, mufflers, intakes, boost modules, headers, and more for various late model cars, trucks, and muscle cars. Flowmaster has designed 12 chambered mufflers, 3 styles of exclusive “laminar-flow” mufflers, and a brand-new line of FLowFX “straight-through” mufflers. This all comes along side 5 different sound categories for their exhaust systems giving the customer a wide array of options to go from mild to wild with the exhaust tones.