A cat-back exhaust on a GMT800 Silverado or Sierra is one of the best value mods available. On a 5.3L or 6.0L truck you get a real sound improvement, 8–15 horsepower at the wheels, and better exhaust scavenging — especially when paired with a tune.
STOCK LIMITATIONS
- Factory exhaust is 2.5-inch diameter — restrictive on the 5.3L and especially the 6.0L
- Single exit rear exhaust on most configurations
- Factory muffler is tuned for quiet, not flow or tone
CAT-BACK OPTIONS
Flowmaster American Thunder
- Aggressive tone, recognizable Flowmaster rumble
- 3-inch piping on most kits — good improvement over stock
- Available in single or dual exit configs
- Popular and widely available — proven fitment for GMT800
Flowmaster Super 44
- Louder than American Thunder
- Great if you want more drone-free sound at idle with decent highway noise
- Works well in combination with an intake and tune
Corsa Sport / Performance
- Quieter at cruise, louder under acceleration — less drone
- More expensive but worth it for daily drivers
TIPS
- Cat-back does not touch the catalytic converters — fully legal
- Dual exit kits exit behind both rear tires for a cleaner look
- 3-inch mandrel bent pipe is preferred for flow
- Pair with a tune to maximize power gains