Gibson 65621 Cat-Back Dual Extreme Exhaust System Stainless Steel

The Gibson 65621 Cat-Back Dual Extreme Exhaust System delivers aggressive performance sound and real power gains for serious truck enthusiasts. Built with stainless steel mandrel-bent tubing, this dual cat-back system exits behind each rear tire at a bold, aggressive angle — improving exhaust flow while giving your truck a commanding street presence.

Engineered and dyno-tuned for the specific application, this system is designed to reduce backpressure and unlock average gains of 15–20 horsepower along with improved torque output. The Gibson Superflow muffler uses a baffled and chambered design with no internal packing, producing a deep, aggressive exhaust note while keeping interior drone to a minimum.

Muffler Specifications:

• Design: Baffled & Chambered Superflow Muffler
• No internal packing
• Minimal interior drone with aggressive exterior sound
• Body: 8 in. round
• Inlet: 3.50 in. center
• Outlet: 3.00 in. dual
• Length: 24 in.

Tip Specifications:

• 4 in. polished T304 stainless steel round slash-cut tips
• Clamp-on fitment
• Inlet: 3 in. | Outlet: 4 in. | Length: 12 in.

Key Features:

• Stainless steel mandrel-bent tubing for maximum flow and long-term durability
• Dual exit behind each rear tire for an aggressive stance
• Includes all hardware and factory-style hangers
• 100% bolt-on installation — no welding or cutting required
• Proudly made in the USA
• Backed by a Gibson Lifetime Limited Warranty

The Gibson 65621 is a complete bolt-on cat-back exhaust kit that installs with hand tools using factory hanger locations. It's the ideal upgrade for truck owners who want proven performance gains, a deep aggressive exhaust tone, and a polished stainless finish that lasts.