After customers complained of the diesel-engine Hummer H1 being underpowered relative to its gasoline counterpart, General Motors began development on what would become the ultimate Hummer, the H1 Alpha. The biggest change came from shoehorning a 6.6-liter Duramax turbodiesel sourced from the GMT560 medium-duty truck under the hood. Extensive modifications were made to ensure it fit into the Hummer chassis, including 23 engine-component changes and a two-inch lift to accommodate the turbodiesel’s taller dimensions.

The Duramax diesel engine of the H1 Alpha was further equipped with a cooled exhaust gas recirculation system and an internal engine cooler. Due to limited space under the hood, the fan system was modified and driven by a special gearbox connected directly to the crankshaft. The fuel and filtration systems were revised, and the H1 Alpha was equipped with main and auxiliary fuel tanks. The cooling system was altered to enable easy cold-starting from temperatures as low as -30 degrees Fahrenheit. Sadly, these alpha Hummers represented the swan song of the brand, with GM shuttering the division after just 729 H1 Alphas were built.

Showing less than 22,000 miles at the time of cataloguing, this Hummer H1 Alpha is finished in yellow over black and tan leather upholstery and sports significant upgrades by Hummer performance expert Predator Inc. Work included a RapTorque ECU, manually adjustable shocks, RapJet stage-three fuel injectors, and “Search & Rescue” center console rack, installed at a cost of more than $10,000. Predator claims these updates elevate Duramax diesel output to nearly 500 horsepower and 700 pounds-feet of torque. Seventeen-inch, forged aluminum, bead-lock wheels are augmented with a central tire-inflation system for adjusting tire pressures from inside the vehicle, which is said to function well,

One of the most recognizable vehicles of all time, this well sorted Hummer H1 Alpha makes a statement both on and off the road. With its improved diesel engine replete with performance upgrades, it represents the ultimate civilian evolution of the iconic military-based vehicle.