DEARBORN, Mich. (September 2, 2026) – Ford’s U.S. Heritage Fleet has completed the recommissioning of a one-of-one, V10-powered Ford Mustang prototype built in secret roughly 25 years ago, returning the long-hidden engineering exercise to running condition with the help of members of its original development team.

Built around the turn of the millennium on what the team has described as a shoestring budget, the prototype began as an exploration of whether a V10-powered Mustang could compete with rivals like the Dodge Viper and Chevrolet Corvette. Ford engineers found the production 6.8-liter Triton V10 too large for the Mustang’s engine bay, so they engineered a bespoke alternative instead: taking castings from Ford’s aluminum 4.6-liter modular V8 and adding two cylinders to create a naturally aspirated 5.8-liter, 351-cubic-inch V10, topped with dual-overhead-cam heads derived from the Mustang Cobra R. Because Ford had no engine control unit designed to manage an odd-firing V10, the car required dual ECUs to run. The completed engine, installed in a modified 1999 Mustang wearing a Cobra R hood, was paired with a Tremec T56 six-speed manual transmission and a Ford 9-inch rear axle, producing 426 horsepower and 400 lb-ft of torque in period.

The one-off Mustang never entered production and spent much of the following decades largely out of public view, at times, according to the Heritage Fleet team, coming dangerously close to disappearing altogether before being preserved within Ford’s Heritage Fleet collection.

“It was one of those cars that almost felt mythical,” said Matt Korczyk, Ford Heritage Fleet manager, who grew up hearing stories about the car before eventually becoming one of the people responsible for maintaining it.

Earlier this year, the Heritage Fleet team began working with members of the car’s original engineering group to bring it fully back to life after years of sitting. The effort focused on new electronics and a fresh look at systems that hadn’t been serviced in decades, with the explicit goal of preserving the car’s original character rather than increasing its performance. On the dyno, the V10 produced more than 510 horsepower at the wheels — a notable increase over its original output, driven largely by recommissioning systems to full working order rather than any performance modifications.

Present for the dyno run were several members of the car’s original engineering team, including Greg Coleman, Jim O’Neill, Paul Vella, Don Masch, and Mike Shelby, along with their supervisor, John Brune. Twenty-five years earlier, the group had spent countless nights and weekends turning the V10 Mustang from an audacious idea into a running reality, machining parts that did not previously exist and proving the concept could work. According to the Heritage Fleet team, the moment was defined less by the horsepower figure than by watching the original engineers see their creation come back to life.

Ford’s Heritage Fleet preserves significant vehicles from the company’s history for use in education, events, and public display. The team has said the V10 Mustang’s survival reflects a broader theme in the fleet’s mission: that preserving a vehicle is ultimately about preserving the people, ideas, and stories behind it, not simply the car itself.red a bespoke alternative instead: taking castings from Ford’s aluminum 4.6-liter modular V8 and adding two cylinders to create a naturally aspirated 5.8-liter, 351-cubic-inch V10, topped with dual-overhead-cam heads derived from the Mustang Cobra R. Because Ford had no engine control unit designed to manage an odd-firing V10, the car required dual ECUs to run. The completed engine, installed in a modified 1999 Mustang wearing a Cobra R hood, was paired with a Tremec T56 six-speed manual transmission and a Ford 9-inch rear axle, producing 426 horsepower and 400 lb-ft of torque in period.

The one-off Mustang never entered production and spent much of the following decades largely out of public view, at times, according to the Heritage Fleet team, coming dangerously close to disappearing altogether before being preserved within Ford’s Heritage Fleet collection.

“It was one of those cars that almost felt mythical,” said Matt Korczyk, Ford Heritage Fleet manager, who grew up hearing stories about the car before eventually becoming one of the people responsible for maintaining it.

Earlier this year, the Heritage Fleet team began working with members of the car’s original engineering group to bring it fully back to life after years of sitting. The effort focused on new electronics and a fresh look at systems that hadn’t been serviced in decades, with the explicit goal of preserving the car’s original character rather than increasing its performance. On the dyno, the V10 produced more than 510 horsepower at the wheels — a notable increase over its original output, driven largely by recommissioning systems to full working order rather than any performance modifications.

Present for the dyno run were several members of the car’s original engineering team, including Greg Coleman, Jim O’Neill, Paul Vella, Don Masch, and Mike Shelby, along with their supervisor, John Brune. Twenty-five years earlier, the group had spent countless nights and weekends turning the V10 Mustang from an audacious idea into a running reality, machining parts that did not previously exist and proving the concept could work. According to the Heritage Fleet team, the moment was defined less by the horsepower figure than by watching the original engineers see their creation come back to life.

Ford’s Heritage Fleet preserves significant vehicles from the company’s history for use in education, events, and public display. The team has said the V10 Mustang’s survival reflects a broader theme in the fleet’s mission: that preserving a vehicle is ultimately about preserving the people, ideas, and stories behind it, not simply the car itself.