This example, chassis SN61, is one of the rare Rally Fighter X1 builds and is currently Montana titled and street legal. It shows purposeful development throughout, centered around a supercharged 6.8-liter GM LS3 by Edelbrock producing approximately 720 horsepower. Power delivery is immediate and effortless, with torque available across the rev range rather than concentrated at the top end. To support the increased output, the transmission was upgraded from the standard configuration to a reinforced GM 4L85E automatic, developed specifically for the X1 project by Zero Gravity. Internals were reconfigured to handle 700-plus horsepower and paired with a billet aluminum torque converter and upgraded clutches. Gear selection is controlled via a PCS column-mounted paddle shifter system engineered and tuned for this build. At the rear, a Currie 9-inch differential with 3.73 ratio gears and heavy-duty internals distributes power through upgraded axles. The four-link trailing arm suspension and welded gusset rear axle housing emphasize durability and off-road intent. Suspension duties are handled by King triple-bypass shocks, delivering approximately 20 inches of rear travel and 18 inches at the front. Cooling capacity was engineered to match the power output. A custom C&R aluminum radiator works alongside dedicated intercooler, transmission, and oil coolers, with both automatic and manual fan control. This system was designed to withstand sustained high-load use in extreme temperatures. Exhaust is routed through a 3-inch stainless steel system with Magnaflow mufflers and custom headers, producing a deep and aggressive tone without excessive harshness. The fuel system employs twin high-flow Bosch pumps with an upgraded regulator to ensure consistent delivery under boost. Braking is managed by four-wheel anti-lock brakes with 13-inch ventilated front rotors and 13.7-inch ventilated rear rotors. The car rides on 17-inch aluminum alloy wheels wrapped in 275/70R-17 tires. A mini tubular front bumper and integrated titanium skid plate underscore the vehicle’s functional design. The exterior is finished in a P-51 Mustang-themed wrap, giving the car a military-inspired aesthetic consistent with its mechanical intensity. The wrap shows fading on the doors, roof, and hood. A small crack is present in the rear bumper. Inside, the cabin reflects the Rally Fighter’s exposed, industrial character. Digital boost and fuel ratio gauges are mounted to the cage. A custom billet aluminum shift knob and e-brake handle were machined from 6061 aluminum with stainless fasteners, replacing the standard pistol-grip control layout. An 8-inch touchscreen integrates a four-camera, 360-degree system that provides real-time maneuvering visibility and recording capability. A six-speaker audio system, air conditioning, and heater retain daily usability. The rear seat has been removed, and the driver’s seat is fitted with a six-point harness. Wear marks are noted on the driver-side front disc and rear caliper. As offered, this Rally Fighter X1 stands as a rare and fully developed example of one of the most unconventional American performance vehicles of its era. With 720 supercharged horsepower, long-travel suspension, and street-legal status, it occupies a niche few vehicles approach and fewer still execute with this level of engineering intent.