Green estimated that the aerodynamic drag of the exposed rear wheels cost the car 20 miles per hour (32 km/h), but since his calculations indicated that they already had much greater speed available than they needed, this was not viewed as a problem.

Although the driver was unhurt "when Walt saw the Wingfoot heading for oblivion he had a heart attack on the spot" and was briefly hospitalized, but released himself in order to repair the car.

At this point there was no time to find another driver, and Green, who had never driven over 130 miles per hour (210 km/h) in his life, was the logical choice because of his familiarity with the mechanics of the vehicle.

On his first timed run he hit 236 miles per hour (380 km/h), but "I hadn't fully anticipated that I'd have the feeling of rattling and banging down the black line like a rock in a can...the salt was a little rough....".

At higher speed, the short front axle began to oscillate, necessitating an increase in the damping of the shock absorbers; but after that last modification, Green found that he could steer with one hand; "I never drifted more than 8 feet [2.4 m] from the black line".

The first run using the afterburner sent the car well over 300 miles per hour (480 km/h); when it was shut down Green felt as if he had "slammed on the brakes, but the airspeed indicator showed that I was still accelerating under regular engine power".

In 1964, Wingfoot Express returned to Bonneville for a week, but the engine never regained the strength shown in their earliest runs, and struggled to pick up speed.

Although the final record run had demonstrated that Wingfoot Express clearly had much more speed available, Green decided to not push his luck and retired from competition, returning to his regular job.

Walt Arfons went on alone to build Wingfoot Express 2 using solid-fuel rockets; peak power and acceleration was enormous, but could not be maintained long enough to set a record over the measured distance.