1970 Ford Mustang Boss 429 Competition Car

The Boss 429, sometimes referred to as the "Boss 9" by blue oval enthusiasts, is arguably one of the rarest and most valued muscle cars from the era. In total, there were 859 original '69 Boss 429s and only 499 for the 1970 model year. The origin of the Boss 429 was as a result of Ford's desire to compete in NASCAR. Ford was seeking to develop a Hemi engine that could take on the Mopar Hemi boys: the 426 Hemi Charger Daytona and Plymouth Superbirds, the monsters Ford wanted to slay to achieve its desire to rule the track. NASCAR required that at least 500 cars be fitted with the competition motor and sold to the general public for homologation purposes.

The Boss 429 engine featured aluminum cylinder heads, which had a modified Hemi-type combustion chamber, which Ford called "crescent". The Boss 429 engine used a single 735 CFM Holley 4-barrel carburetor on an aluminum intake manifold. All these cars had the Hurst competition shifter and 4-speed manual transmissions, and the Boss was rated very conservatively at 375 HP, while actual output was believed to be well over 500 HP.

Mustangs were simply too small to accept the massive Boss 429 engine, so Ford hired Kar Kraft of Brighton, Michigan, to modify existing 428 Cobra Jet and Super Cobra Jet Mach 1 Mustangs. Modifications included widening the shock towers and extending out the inner fenders. The mounts for the front suspension were chopped and displaced to create room for the block and exhaust manifolds. The battery was repositioned to the trunk, and a stiff .75-inch sway bar was added to the rear end to improve handling since the car was now nose heavy. It was also equipped with a 3.91-ratio rear axle with a Traction-Lok limited-slip differential. In addition, a hole was cut in the hood, and a manually controlled hood scoop was added. Other features included a front spoiler and color-keyed dual racing mirrors.

While the Boss 429 was an unusual platform to build a road race car from, as the 429 engine is very heavy and leads to unequal weight distribution and poor handling characteristics, the extra power of the 429 helped make up for time in the straights.

This Boss 429 was purchased new on January 7, 1970 at Jim Blackman Ford in Sebring, Florida. It was originally a Calypso Coral street car that was converted to race specs in 1974 by its first owner, Neil Potter. This is "Orange Blossom III" and is one of only two Boss 429s known to have been raced in the IMSA Camel GT series. It raced 1975-77 in events like the Sebring 12 Hours of Endurance and the 24 Hours of Daytona, and it competed with all the best sports cars of the period.
Retired after the 1977 race season, the car was placed into a storage building at the Sebring race track. After a tornado in 1983, the car was moved from its track storage to Potter's barn, where it was disassembled for future restoration. In 1985, Potter finally sold his car and parts as a basket case to the second owner, who planned to do a complete the restoration. It passed to the cars third owner in 1990, still in unrestored condition. A complete restoration began in 2005 and required extensive sheet metal repair. The comprehensive rotisserie restoration was completed in 2009, and the car was subsequently shown at the Mid America Shelby meet that same year, where it was awarded first in its class and listed in the Boss 429 registry.