Ford’s Secret Mid-Engine Mustang

1969 Mustang Mach I rear window viewIn 1969, Ford built a single prototype for a mid-engined version of the Boss 429 Mustang. Here’s the story on this wild machine. 



We’ve teased a bit of this tale before here at Mac’s Motor City Garage, including it in the feature Five Forgotten Ford Mustangs (April 14, 2014). Here’s more. Built by Ford Motor Company’s Special Vehicles unit and its private Detroit-area skunkworks, Kar Kraft, this fascinating 1969 project was known internally as the LID Mustang. LID was short for Low Investment Drivetrain—a mid-engine configuration done on the cheap, using as many off-the-shelf components as possible.

One notorious issue with the production Boss 429 Mustang of 1969-1970 (1,358 examples built) was its poor weight distribution, the result of cramming a big, iron hemi V8 between the front wheels of a lightweight Mustang coupe. The LID concept addressed this problem by relocating the engine from the front to the rear. Here’s how the deed was done.


1969 Mustang LID drivetrainA standard Boss 429 engine and C6 automatic transmission were turned around backward and installed in a removable rear subframe, with the engine centered directly over the rear axle centerline. A custom-built transfer case turned the output 180 degrees and fed it to a 9-inch Ford rear axle, which was converted to independent operation with articulated half shafts and u-joints. A special axle housing incorporated an engine mount and pickup points for the Koni coilover shocks and rear control arms. The modular, drop-out layout was obviously devised with low-volume production in mind.


1969 Mustang Mach I LID left sideOn the outside, the LID Mustang looked much like a standard 1969 Mach I Sportsroof, with little to give away the revised engine location. The stamped steel wheels, eight inches wide at the rear and six inches in the front, were reverse offset (in front-wheel drive fashion) to preserve the stock track width, then disguised with full wheel covers borrowed from a Lincoln. The rear seat was removed and the area trimmed with black carpeting, while up front, the former engine compartment housed the battery, radiator, and air-conditioning condenser, with electric fans to provide cooling.


1969 LID Mustang rear hatchFor access to the big V8 out back, the rear glass was replaced with a Sports Slat rear louver assembly mounted on hinges and folding struts. The LID project was a complete success in this way: The Boss 429’s weight distribution was changed from 60/40 percent front to 40/60 rear. But to the engineers’ surprise, except for a reduction of wheelspin, there was no significant improvement in performance. With that discovery, the LID Mustang program was stopped in its tracks.

So what was the fate of the lone mid-engine Boss 429? According to a short article on the beast in the December 1970 issue of Motor Trend, at that point it was awaiting its appointment with the crusher at a Detroit-area salvage yard. Since the unique Mustang hasn’t been seen since, we presume that’s where this story ends.


21 thoughts on “Ford’s Secret Mid-Engine Mustang

    • This is a bogus story. Another one of those “soldier dies in Viet Nam and mother sells his 1961 Chevrolet for $500.” The Chevrolet turns out to be a Corvette. Those stories are bogus as well. Look at the struts in the pic. The one on the Drivers side is down on the ground. The other is sitting atop of the engine valve cover. I had 3, 69 Mach Ones and the Luvers didn’t have anything to hold them up.

      • You are wrong about the struts Tommy. Look closer, they are two piece folding bars. Those aren’t shadows at the bottom they are the second piece of the strut.

  1. On the last picture, it has a ’70 taillight panel, but it still has the ’69 side scoops.

  2. As a UM intern at Ford Special Vehicles, I was never allowed to drive the rear engine Mustang, but I did get to ride in it. IMO the stock Boss 429 engine, which was very anemic in road tune, was the car’s limitation. With all its rear weight, the car could not even spin the tires. A cam and intake change would have made all the difference in the world. The production Boss 429 was a dog as everyone knows.

    • The car was never crushed. I know the man who has it in his garage. I’ve seen it myself.

      • Would it be possible to pass on contact information for Mustang Medic in Palm springs to the current owner? They do restoration videos as they work on Mustangs and I’m sure they would love to hear from the guy that ownes it and what it’s current condition is. At the time of this posting their location is: MustangMedic / co William
        36655 Sunair Plaza, Cathedral City, CA 92234 – 760-413-4445

  3. The Boss 429 is a one off body anyway with the notched spring towers.
    This version would have been a 2 seat car,, though the back seat on those things is a no go for anyone over 5 foot 6.
    The noise factor would have been interesting. A Porker and a Pantera are decidedly noisy inside. The auto too may have been a turn off for potential buyers.
    Those dreadfull bias belt tyres would not have helped either, some decent [period] radials may have transformed it. Those polyglass and Wide Ovals were truly terrible! worse, the bloody things are still made!

  4. I used to say that I could count every Mustang I ever wanted on the fingers of one hand. The second hand has now been called in.

    • I’ve lusted after this car for years Myron!! It’s pretty amazing mechanically. Probably drove like a monster.

  5. I have seen a photo of a white boss 9 parked in a lot at ford grounds 3/4 front shot, also a closeup of the engine thru the rear window, no window slats at that time it was a ’69. ps I drove # 50 Boss429 almost 20 years ,If I had it back, I would probably still be driving it!

  6. In the late 80’s there was a mustang in Great Bend Kansas that if not this car was attempt at making one like it.

  7. Don’t if wear glasses, but put them on the struts are in side what was the window weld, before you post anything, do your homework

  8. Was this car sold at Barrett-Jackson last month? My neighbor said that he saw a mid engine ’69 but only saw part of that segment.

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