It looks like it might have a cargo hold full of groceries, or better yet--three kids in the back, but that subtle-looking all-black Chevy Trailblazer is actually a fire-breathing beast just waiting to be unleashed. Sporting a 427ci small-block V-8, this Chevy was purpose-built to haul the mail. It may look like any other Trailblazer, but that was the point.

Purchased new and immediately delivered to Katech Performance in Clinton, Michigan, the Trailblazer SS was to be enhanced in the only way Katech knows how: horsepower. Starting by removing the factory LS2, the team at Katech installed one of its 427ci short-block engines, which was complete with forged pistons, rods, and crankshaft. The block uses centrifugally-cast ductile iron sleeves for maximum performance. Katech also installed a performance LS2 throttle-body and Corsa exhaust for an incredible sound. Keeping the engine cool are dual SPAL electric fans with a Ron Davis aluminum radiator and wiring from Vector Motorsports. Vector also supplied the cool-air intake. Katech finished off the engine bay with its own valve covers and coil relocation kit. RPM Transmission stepped in and built the 4L70E transmission with a Precision 2,800 rpm stall torque converter to handle the 540 lb-ft of torque. As soon as the accelerator is applied, 520 horses roast the factory 20-inch tires.

Exterior modifications were left minimal to keep the stealth appearance and include a billet grille and custom-painted SS emblems. Inside the Trailblazer SS, Caravaggio leather was used to upgrade the steering wheel, shifter boot, and center console. Several plastic pieces received hugger orange paint, which provided just the right amount of contrast to the all-black interior.

Built to literally fly under the radar, this Trailblazer SS is exactly what the Chevrolet engineers wish they had created.