The drag pack, power steering, power front disc brakes, and competition suspension were aimed precisely at the 426 Hemi in the ‘Cuda nemesis. Or any other GM-spawned muscle cars of that era, all devoted to dethroning the Mustang.
That brings us precisely to the story’s heart: the legendary 429 ci (7-liter) power plant. It was solely dedicated to the Mustang. After careful analysis, the Ford executives chose their most successful car to bear the new engine. So cautious of analysis, in fact, that they completely overlooked one minor detail: the engine bay wasn’t big enough for the mighty Nascar-ready engine.
The Kar Krafts division squeezed the 429 in the car, but no room was left for air conditioning. And the big engine posed another challenge: weight. It made the car nose-heavy. Engineers countered by moving the battery in the trunk and fitting a 3/4″ sway bar at the rear. The anti-roll bar was a Mustang-first, making the 429s best handlers amongst big-engine Mustangs.
To make the most of the might of the big block under it, the hood received a massive scoop (the biggest one in any factory-production Mustang). After they had finished with it, the engine delivered 375 bhp and 450 lb-ft (610 Nm) of torque. This allowed an 8,000 RPM rev counter to take the central position alongside the 120 mph speedometer. As it so happens, this car it is the first to be fitted with an emissions control system, complying with then-newly introduced federal regulations.
Four-speed manual transmission sent the power to the 3.91:1 ratio rear axle, which had a traction-lock limited slip diff for better track performance. To serve the same purpose, an oil cooler was thrown in the engine compartment to permit high revs over an extended period.
This KK number #2073 sports several other optional extras: a functional front air spoiler and F60X15 belted raised white leather tires. Inside, a convenience group (standard for all 1970 Boss 429s ), an electric clock, and a rim blow-deluxe steering wheel. The www.motorcarclassics.com/1970-ford-mustang-boss-429-c-894.htmdocumentation for this rare Boss consists of owners’ manuals, an original spare inflator, Deluxe- and Elite- Marti reports, and the original invoice.