Unless there's a 1,201-horsepower Duramax truck running around out there that we don't know of, this black '05 Chevy crew cab can lay claim to the highest horsepower Duramax around. The LLY motor has put down some impressive numbers in the past few months, hitting a best 1,199.4-horsepower at 2,133.7 lb-ft of torque at the rear wheels on Bully Dog's dyno. Those numbers come with a hefty dose of nitrous. The truck, owned by James Brindle, runs an ATS Aurora 6000 turbocharger and an ATS Extreme transmission, with a machined engine block and fully built internals. The engine has gone through several rebuilds before finally reaching its peak on the horsepower charts, most recently built at Custom Auto's shop by Dimitri Miller. Along the way to 1,200 horsepower, this truck has seen expanded up pipes, cracked, broken and melted pistons and timing index key failures. But it's also thrown a few punches, too. At Bully Dog's Dog Days of Summer dyno event in 2008, this truck broke the dyno's drive shaft when the second nitrous solenoid was activated.