Description
Overview
The Flowmaster American Thunder Crossmember-Back Exhaust System is a complete true dual upgrade engineered for the classic 1964-1967 GM A-body equipped with a V8 engine. Built to bolt on and deliver serious muscle-car character, this American Thunder system replaces your restrictive factory setup with free-flowing 2.50-inch mandrel-bent stainless steel tubing that promotes maximum performance from the crossmember back. Designed specifically for 2WD applications, it brings modern flow and legendary Flowmaster tone to one of GM’s most iconic platforms.
Sound and Performance
At the heart of the system is a pair of large-case Super 40 Series mufflers that produce a moderate to aggressive interior and exterior tone. This is the exhaust for the enthusiast who wants their performance to be heard, without an overpowering drone. A built-in H-pipe/balance tube ties the two banks together, smoothing exhaust pulses and helping the V8 breathe evenly for a rich, throaty note. As with all Flowmaster systems, the payoff extends beyond sound to improved throttle response, power, and mileage.
Design and Fitment
The true dual 2.50-inch mandrel-bent stainless steel tubing resists corrosion and maintains consistent diameter through every bend for clean, unrestricted flow. The dual tailpipes exit at the rear corners of the car and angle down beneath the rear bumper, giving your A-body a strong, muscular stance that looks as good as it sounds. Everything needed to complete the job is included, so installation is straightforward on the right vehicle.
- Fits 1964-1967 GM A-body with a V8 engine (2WD)
- 2.50-inch mandrel-bent stainless steel tubing for maximum flow
- Built-in H-pipe/balance tube for even, refined exhaust pulses
- Pair of large-case Super 40 Series mufflers included
- Dual tailpipes exit at the rear corners, angled down under the rear bumper
- All hangers and necessary hardware included for installation
- CARB (California) compliant, Emission Code 5
What to Know Before You Buy
This American Thunder system ships as a kit with the Super 40 mufflers included. Exhaust tips are sold separately, allowing you to finish the look exactly the way you want. A heat shield is not included. The tubing carries a silver pipe finish, and the system is covered by Flowmaster’s Lifetime Limited Warranty for lasting peace of mind. Please note this product carries a California Proposition 65 warning.
If you’re restoring or upgrading a 1964-1967 GM A-body and want the unmistakable Super 40 sound backed by genuine performance gains, the Flowmaster American Thunder Crossmember-Back Exhaust System delivers the complete dual package with the fit, flow, and tone the platform deserves.
