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Supplier details checked 2026-09-23 · Test catalog
Fits 1973-1974 Chevrolet and GMC C10, C20 2wd with V8 engines.
Flowmaster American Thunder Crossmember-Back Exhaust System
Does Not Include Header Reducers or Downpipes for Factory Manifolds
Super 44 Series Mufflers for Deep Powerful Sound
Includes Hangers and Hardware for Installation
Mandrel-bent 16-gauge Aluminized Steel Tubing
Aggressive to Moderate Exterior Exhaust Tone
Crossmember-Back True Dual Exhaust System
H-pipe Crossover for Maximum Power
Does not include downpipes for factory manifolds or header reducers.
Flowmaster 73-74 GM C10/C20 American Thunder Header-Back Exhaust System
7374 GM C10C20 HEADER BACK AMT
SYS 73-74 GM C10/C20
This American Thunder exhaust system was specially designed for 1973-1974 Chevrolet and GMC C10 and C15 1/2 ton and 3/4 ton 2wd trucks and is perfect for the person looking for moderate to aggressive interior and exterior sound levels. The Crossmember-Back exhaust system comes complete with a built-in H-pipe crossover, all mandrel-bent 2.50-inch aluminized steel tubing, a pair of Super 44 Series performance mufflers and your choice of tailpipe exits. Either dual out rear under the bumper for a muscular look or dual out the sides behind the rear tires for that classic truck look. The system includes all hardware necessary for installation and is designed to accommodate both long and short wheelbases, with either an automatic or manual transmission and provides adequate clearance for substantially lowered vehicles. The exhaust system is covered by our 3-year Limited Warranty. Notes: Does Not include exhaust tips, header reducer cones or downpipes for factory manifolds.
SYS 73-74 GM
