Ford Almost Gave Us a Mid-Engine Mustang BOSS 429 In 1969
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Ford Almost Gave Us a Mid-Engine Mustang BOSS 429 In 1969

A crazy, mid-engine Ford Mustang BOSS 429 existed and it almost went into production back in 1969

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Performance versions of the Ford Mustang have always been sought-after, by collectors. We have models like the original Shelby GT350 R, Shelby GT500, or BOSS 302, but for many, the top of the cherry, the big daddy, is considered to be the BOSS 429. But for all its performance credentials, the BOSS 429 had weight-distribution issues, which is why, in 1969, Ford decided to experiment with a mid-engine version of the BOSS 429, dubbed the LID Mustang.

The Ford Mustang BOSS 429 We Know

Ford Almost Gave Us a Mid-Engine Mustang BOSS 429 In 1969 High Resolution Exterior
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The Mustang BOSS 429 was produced from 1969 to 1970, alongside the BOSS 302. While the BOSS 302 was produced for the Trans Am Racing Series, the BOSS 429 was meant to fulfill Ford’s needs to homologate the 429 V-8 engine for the NASCAR series. The big V-8 featured combustion chambers with a semi-hemispherical design, which is why it’s often referred to as Ford’s Hemi.

Like other Muscle cars from that era, the BOSS 429 engine was underrated. The output was rated at 375 horsepower at 5,200 RPM and 450 pound-feet (610 Nm) at 3,400 RPM. However, independent dyno-tests have proven that the engine actually makes around 420 horsepower at 5,600 RPM.

1969 Ford Mustang Boss 429 specifications
Engine: 7.0-liter V-8
Horsepower: 375 HP @ 5,200 RPM
Torque: 450 LB-FT @ 3,400 RPM
0-60 mph: 6.5 seconds
Top speed: 140 mph

Weight Distribution Issues

1969 Ford Mustang Boss 429 High Resolution Exterior
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The 429 featured forged steel internals and was capable of even more power in race-trim, but for all its capabilities, it had one drawback – weight. Despite having aluminum heads, Ford’s Hemi still weighed in at 680 pounds (308 kg). This resulted in a 60/40 weight distribution, where 60 percent of the weight was at the front axle.

Where the LID Mustang Came In

Ford engineers knew the 60/40 weight distribution was not ideal for performance applications so, according to, Ford turned to its Special Vehicles unit and its Detroit-area skunkworks, Kar Kraft, in order to create a BOSS 429, with the big V-8 stuffed in the back. An entirely new sub-frame was developed for the LID Mustang that would accommodate the 429 cubic-inch V-8, C6 automatic gearbox, and nine-inch rear axle, which were turned 180 degrees. The axle, itself, was converted to independent operation, with articulated half-shafts and u-joints, as explained by

Access to the longitudinally-mounted engine was gained through the rear windshield, which was louvered. The LID still had a rear trunk, at least according to the images, but the rear seats had to go, in order to fit the engine in the middle. To top it all off, the LID Mustang sat on Koni coil-over shocks and rear control arms. The frontal area that used to be the engine bay now accommodated the battery, radiator, air conditioning condenser, and electrical cooling fans.

What Does LID Stand For?

The LID moniker stood for Low Investment Drivetrain. Ford wanted to sort the BOSS 429’s weight distribution problem for as little money as possible (or at least try). They used as many off-the-shelf parts as possible, to fabricate the new sub-frame and move the V-8 and most of its periphery and drivetrain components to the rear of the car. With this in mind, don’t be so quick to compare it to European exotics, which had an actual budget for research and development.

What Are The Visual Differences?

1969 Ford Mustang Boss 429 High Resolution Exterior
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The exterior proportions of the LID Mustang were identical to the front-engine Mustang BOSS 429. However, despite having the 429 cubic-inch V-8, the LID Mustang was trimmed like a Mach 1 Sportsroof. There was even a front hood scoop, in order to full the public. The original steel wheels, eight inches wide at the front, six inches wide at the rear, were reverse-offset, in order to preserve the stock track width and then disguised with full wheel covers from the Lincoln parts bin.

Why Didn’t Ford Make It?

Ford’s exercise in transforming the Mustang BOSS 429 from a front-engine to a rear-mid-engine layout bore interesting results. The weight distribution was effectively reversed, from 60/40 to 40/60. However, despite reducing wheel spin, not much was gained, in terms of driving dynamics. Because the performance gains were deemed insignificant, the project was scrapped.

What Happened To the LID Mustang?

Ford Almost Gave Us a Mid-Engine Mustang BOSS 429 In 1969
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According to an issue of Motor Trend magazine from December 1970, the only development prototype of the LID Mustang was destined for the crusher. For a long time, that was believed to be the case, but the website mentions updates from “credible sources that used to work at Ford”, according to which “there’s an excellent chance” that the car isn’t scrapped. In fact, one of these “credible sources” claims that the car has been sent to a “fenced-in bullpen” where it sits with other discarded concepts.

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Dim Angelov
Dim Angelov
Born in 1992, I come from a family of motoring enthusiasts. My passion for cars was awoken at the age of six, when I saw a Lamborghini Diablo SV in a magazine. After high school I earned a master’s degree in marketing and a Master of Arts in Media and Communications. Over the years, I’ve practiced and become skilled in precision driving and to date have test driven more than 250 cars across the globe. Over the years, I’ve picked up basic mechanical knowledge and have even taken part in the restoration of a 1964 Jaguar E-Type and an Alfa Romeo Giulia Sprint. Lately, I’ve taken a fancy to automotive photography, and while modern cars are my primary passion, I also have a love for Asian Martial Arts, swimming, war history, craft beer, historical weapons, and car restoration. In time, I plan my own classic car restoration and hope to earn my racing certificate, after which I expect to establish my own racing team.  Read full bio
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