The Boss 429 is recognized as being among some of the rarest and highly valued muscle cars to date. In total there were 1359 original Boss 429s made. The origin of the Boss 429 was to fulfil Ford’s need to homologate the 429 semi-hemispherical engine for NASCAR racing. Ford was seeking to develop an engine that would better compete with the 426 Hemi from Chrysler in NASCAR’s Grand National Division, now known as the NASCAR Cup Series.
@NASCAR‘s homologation rules required that at least 500 cars be fitted with this motor and sold to the general public. After much consideration, it was decided by Ford that the Mustang would be the car that would house this new engine. Production of the Boss 429 began in 1968 at the Ford Rouge plant, where front apron assemblies revised to accept the large Boss 429 engine were installed during vehicle construction. These also provided a stronger and cleaner front structure, important considerations on such a performance car, and were coupled with reworked front fenders. The cars were then shipped to Kar Kraft’s new assembly plant in Brighton, Michigan for engine installation and further modifications.