Who was the head engineer for the original Mustang's T-5 project?

Donald N. Frey was the head engineer for the original Mustang’s T-5 project.

Frey was Lee Iacocca’s assistant general manager and chief engineer at Ford. He supervised the overall development of the Mustang, helping bring the car from an internal project to production in a record 18 months. Iacocca, then Ford Division general manager, championed the project and helped secure its priority within the company.

The project’s early T-5 prototype was a two-seat roadster with a mid-mounted engine. Ford later developed the concept into the four-seat Mustang that debuted for the 1965 model year. The production car used the compact Ford Falcon’s platform, which helped keep costs and development time under control.

The other names in the choices were associated with different parts of the Mustang story. Gale Halderman was a major stylist whose side-view sketch influenced the car’s shape, while John Najjar was a Ford designer and Lee Iacocca was the executive champion—not the project’s head engineer.