Ford Mustang Boss 429
The mythical Mustang Boss 429 is a proper Ford muscle car legend. Ford conceived it in 1969 as a pure racing engine they intended for use in the NASCAR championship. The Boss 429 featured a totally different engine architecture than the rest of the Ford big blocks. The Boss 429 was much wider and had semi-Hemi combustion chambers.
As a result, it could achieve higher revs, better flow inside the head and it produced more power and torque. Rated at 375 HP by the factory, this unit produced over 500 HP in reality and much more in race trim. Ford decided to put this engine into the Mustang, creating a limited production Boss 429.
However, NASCAR decided not to homologate it since the series only accepted intermediate and full-size cars, and the Mustang was a pony car model. So, Ford homologated the Torino Talladega as the body and the Boss 429 as the engine. They participated in the 1969 season with Torinos and Mercury Cyclones powered by the Boss 429 engines. Those cars proved successful, winning 30 out of 54 races that year.