The Original Ford Mustang Indy Pace Car Had a GT40 Race Engine

Bill Ford took a rare 1964.5 Mustang Indy Pace Car to Jay Leno's Garage. This is the actual car that paced the field for the 1964 Indianapolis 500. To meet the speed requirements for a pace car, it was fitted with a detuned engine from the Mark I Ford GT40 race car. 

The earliest Ford Mustangs are considered 1964.5 models, since they went on sale in April 1964 at the same time the car debuted. One was famously sold a couple of days before the official reveal, but it didn't have anywhere near the horsepower of the pony car featured here. That's because it has a detuned Ford GT40 engine under the hood, installed so it could pace the field at the 1964 Indianapolis 500.

This isn't one of the few Mustang pace car replicas built back in the day. It's the actual car used on the track at Indy. Ford Executive Chairman Bill Ford recently took the special 'Stang to Jay Leno's Garage, where he shared the story of how this early-production Mustang came to life.

"Pretty much everything in this car was modified for Indy," Ford tells Leno in the video. "The regular Mustang just couldn't get up to the speed required, which was 140 mph. That's what you had to do in those days to have a pace car."

So with barely a month to go before race day, three 1964.5 Mustangs were picked and sent to Holman-Moody in North Carolina for modification. The stock 164-horsepower, 260 cubic-inch V-8 was replaced with a detuned version of the early Ford GT40's 289 cubic-inch engine. According to Ford, power went up to 450 horses, while a modified manual transmission was bolted in to handle it all.

Looking at the car, it doesn't appear any different than other early Mustang convertibles, right down to the wheels. When Leno starts it up, however, it clearly has that old GT40 rumble. As per usual, he takes the car for a drive with Ford in the passenger seat, but they don't cruise the streets of California. At least not right away—we're treated to several laps around an active airport before the duo venture into the public. Perhaps Mr. Ford was a bit nervous taking a priceless Mustang Pace Car into SoCal traffic. Of the original three, this is the only one that still exists.