Description
Overview
The Flowmaster American Thunder Crossmember-Back Exhaust System is purpose-built for 1973-1974 Chevrolet and GMC C10 and C15 1/2 ton and 3/4 ton 2WD trucks. Engineered from the crossmember back, this complete system delivers the moderate-to-aggressive interior and exterior sound levels that classic truck owners crave, while giving your Chevy or GMC hauler a serious performance upgrade. Everything needed to transform your truck’s exhaust note and flow arrives ready to bolt on.
At the heart of the system is a pair of Flowmaster Super 44 Series performance mufflers, delivering that unmistakable aggressive tone without unbearable drone. Combined with mandrel-bent 2.50-inch aluminized steel tubing and a built-in H-pipe crossover, this setup promotes smooth exhaust flow and a deep, muscular sound signature that sounds as good as it performs.
Key Benefits
Every component is designed to work together as a complete crossmember-back package. The mandrel-bent construction maintains a consistent 2.50-inch inner diameter through every bend, protecting flow where lesser crush-bent systems restrict it. The aluminized steel tubing resists corrosion, while U-bolt clamping and flanged connections make installation straightforward. Best of all, this system is CARB (California) compliant, so you can enjoy the American Thunder sound while staying street-legal.
- Complete crossmember-back system with a built-in H-pipe crossover for balanced flow and tone
- Mandrel-bent 2.50-inch aluminized steel tubing in a silver finish
- Pair of Super 44 Series performance mufflers included for an aggressive-to-moderate sound level
- Dual tailpipe configuration with your choice of exit style
- U-bolt clamping and flanged mounting with all necessary installation hardware included
- CARB compliant (Emission Code 5) and backed by a 3-year Limited Warranty
Choose Your Tailpipe Exit
Tailor the look to your truck. Select dual-out-the-rear exits under the bumper for a bold, muscular stance, or opt for dual-out-the-sides behind the rear tires for that timeless classic truck appearance. Either configuration keeps the aggressive Super 44 tone front and center. Note that exhaust tips are sold separately, allowing you to finish the system exactly the way you want.
Fitment
This American Thunder system fits 1973-1974 Chevrolet and GMC C10 and C15 1/2 ton and 3/4 ton 2WD trucks. It is designed to accommodate both long and short wheelbases, works with either an automatic or manual transmission, and provides adequate clearance for substantially lowered vehicles. Please note the system does not include exhaust tips, header reducer cones, or downpipes for factory manifolds.
Upgrade your classic C10 or C15 with a genuine Flowmaster American Thunder system engineered for flow, sound, and lasting durability.








