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One well-known 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-block HEMI V8 between the front wheels of a light, short-wheelbase chassis. The LID concept addressed this problem by relocating the engine from the front to directly over the rear wheels. Here’s how the deed was done.
A standard Boss 429 engine and C6 automatic transmission were turned around backward and installed in a fabricated, removable rear subframe, with the engine centered directly over the rear axle centerline. A custom-built transfer case, similar to a marine drive, 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—and at a much lower cost than the conventional solution, an exotic and expensive European transaxle.
On the outside, the LID Mustang was trimmed not like a Boss 429 but like a standard 1969 Mach I Sportsroof, with little to give away the revised engine location. Note: There was even a hood scoop up front. 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 taken from the Lincoln parts bin. 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.
For 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 static weight distribution was reversed 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.