Outlaw, that's called an exhaust cut-out. The most common types are installed between the headers and the catalytic converter. They're 'cut-out' either with a cable (like the hood-release cable), electronically, or by undoing some wingnuts. The wingnut type is obviously the least expensive and easiest to install. You must have a welder install the cutout.
Mostly exhaust cutouts are used on street/strip drag cars cause you can be legal and drive on the street, then go to the strip and remove all your exhaust backpressure. Due to the design of our motors, an exhaust cutout probably will NOT help performance, and might hurt it. This is because our motors need some backpressure in order to generate torque. Your upper rpm hp may increase, but you'll lose all your low-end 'grunt'.
Not to mention that cutouts are illegal to have open on the street due to your bypassing the catalytic converters and muffler. Your truck will smell, be loud, and might get exhaust into the cabin.
