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Manufacturer information. Check the part number and installation requirements for your vehicle.
Supplier details checked 2026-09-23 · Test catalog
1955-1957 Chevrolet cars with V8 engine. - Aggressive to moderate sound
Flowmaster American Thunder Crossmember-Back Exhaust System
Does Not Include Header Reducers or Downpipes for Factory Manifolds
H-pipe Crossover for Maximum Power and Deep Tone
Super 44 Series Mufflers for Deep Powerful Sound
Includes Hangers and Hardware for Installation
Mandrel-bent 16-gauge Stainless Steel Tubing
Moderate to Aggressive Exterior Exhaust Tone
Crossmember-Back True Dual Exhaust System
Lifetime Limited Warranty
Fits 1955-1957 Chevrolet cars with V8 engine. Does Not fit convertibles or wagons.
Flowmaster 55-57 Chevrolet 2.5in. American Thunder SS Crossmember-Back Exhaust System
5557 CHEVY 25 AMT 409S
SYS 55-57 CHEVY 2.5"
For the person who is looking for a complete Crossmember-Back dual exhaust system for your 1955-1957 Chevy coupes and sedans. This American Thunder® system is manufactured from 2.50-inch mandrel-bent stainless steel for maximum performance and longevity, and includes a built-in H-pipe for a mellow smooth tone eliminating back rap on deceleration. The system includes a pair of Super 40® Series performance mufflers for a deep exterior sound, with a moderate interior tone and dual tailpipes tucked up high for clearance and exit straight out the back under the rear bumper. Like all Flowmaster® systems, the benefits include improved throttle response, power and mileage. Designed for an easy fit, these systems include all necessary parts and hardware for easy installation. Covered by our Lifetime Limited Warranty. Notes: Does Not fit wagons or convertibles.
SYS 55-57 CH
