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Manufacturer information. Check the part number and installation requirements for your vehicle.
Supplier details checked 2026-09-23 · Test catalog
Fits 1964-1972 GM A-Body with V8 engines, 2.5" pipes - Aluminized Steel - Aggressive to moderate sound
Flowmaster American Thunder Crossmember-Back Exhaust System
Fits most 1964-1972 GM A-Bodies with V8 engines and aftermarket long tube headers.
Includes Hangers and Hardware for Easy Installation
Two Exit Style Choices: Slash Cut or Turndown
Mandrel-bent 16-Gauge Aluminized Steel Tubing
Moderate to Aggressive Exterior Exhaust Tone
Built-in Balance Pipe Equalizes Pressures
Super 40 Series Performance Mufflers
Flowmaster Quality & Reliability
Crossmember-Back System
Does Not Include Factory Manifold Downpipes or Header Reducer Cones
Flowmaster 64-72 GM A-BODY 2.5 in. American Thunder Crossmember-Back Exhaust System
6472 GM ABODY 25 IN AMT
SYS 64-72 GM A-BODY
This American Thunder® Crossmember-Back exhaust system is custom designed for most 1964-1972 GM A-body cars and is for the person looking for a complete 2.50-inch dual exhaust system with a moderately aggressive exterior tone and a moderate interior sound. With easy fit in mind, these aluminized steel systems feature all mandrel-bent tubing, an H-pipe to equalize the exhaust pressures for maximum performance and deep sound and includes a pair of specially selected Super 40™ mufflers. The mandrel-bent 2.50-inch tailpipes tuck up out of the way for maximum clearance and offer you two choices of tailpipe exit styles. Like all Flowmaster® systems, benefits include improved throttle response, power, and mileage. Designed for an easy fit, these systems include all necessary parts and hardware for an easy installation and is covered by our 3-year Limited Warranty.
SYS 64-72 GM
