Description
Overview
The Flowmaster American Thunder Crossmember-Back Exhaust System transforms classic muscle car performance and sound with a purpose-built, all stainless steel dual exhaust engineered specifically for 1967-1974 Chevrolet Camaro, Pontiac Firebird, and 1968-1974 Chevrolet Nova models. Designed for 2WD applications, this complete crossmember-back system delivers the deep, unmistakable tone Flowmaster is known for while retaining the classic factory-inspired routing your muscle car deserves.
At the heart of the system is Flowmaster’s exclusive 80 Series Crossflow muffler. The crossflow design places the muffler in the factory location behind the rear axle, preserving full ground clearance beneath the car while still delivering all the performance benefits of a true full dual exhaust. It’s a smart engineering approach that gives you serious flow without sacrificing the ride height and clearance that matter on a classic.
Sound and Performance
This system produces a moderate tone both inside and out — deep, rich, and smooth without being overwhelming in the cabin. All mandrel-bent dual 2.50-inch pipes maintain consistent diameter through every bend for optimum exhaust flow, and the included H-pipe crossover adds to the deep, smooth character while minimizing back-rap on deceleration. Dual 2.50-inch stainless steel tailpipes finish the system, delivering a rich exhaust note and strong performance across the rev range.
Build Quality and Materials
Built from durable 409S stainless steel, the American Thunder system is engineered to stand up to the elements and years of driving. The pipes carry a black finish, and the entire system arrives ready to install with all necessary parts, hardware, and illustrated instructions included. Note that exhaust tips are sold separately and no heat shield is included, giving you the flexibility to finish the look your way.
Highlights
- All stainless steel 409S construction with a crossmember-back configuration
- Exclusive 80 Series Crossflow muffler included, positioned in the factory location behind the rear axle
- Mandrel-bent dual 2.50-inch pipes with H-pipe crossover for deep, smooth tone
- Dual stainless steel tailpipes for a rich sound and optimum performance
- Moderate sound level — deep and refined inside and out
- Includes all parts, hardware, and illustrated instructions
- CARB (California) compliant with Emission Code 5
Fitment
Engineered for 2WD 1967-1974 Chevrolet Camaro and Pontiac Firebird, and 1968-1974 Chevrolet Nova. This system is CARB compliant for use in California, and carries a California Proposition 65 warning.
Like all Flowmaster stainless steel street products, the American Thunder Crossmember-Back Exhaust System is backed by Flowmaster’s Limited Lifetime Warranty — giving you lasting confidence in both the sound and the build.
