5. Boss 429
The mythical Boss 429 engine is a proper muscle car legend. Conceived in 1969 as a pure racing engine intended for use in NASCAR championships, the Boss 429 featured a totally different engine architecture than the rest of Ford’s big blocks. The Boss 429 was much wider and had semi-Hemi combustion chambers that achieved higher revs. It also offered better flow inside the heads, which ultimately produced more power and torque. Rated at 375 HP by the factory, this unit actually put out over 500 HP and much more in race trim.
Ford decided to put this engine into the Mustang, creating a limited production Boss 429. But, NASCAR didn’t homologate it since they only accepted intermediate and full-size cars. The Mustang was a pony car model. So, Ford homologated the Torino Talladega as a body and the Boss 429 as an engine. They participated in the 1969 season, using the Torino and the Mercury Cyclone with a Boss 429 engine.
Those cars proved successful, winning 30 out of 54 races that year. The secret was the engine because Ford designed the Boss 429 to run at a high rpm for long periods of time. This way, it could achieve its peak power high in the rpm range. The Mustang Boss 429 never fulfilled its street racing potential since the mighty engine needed long super speedway tracks to show its true power, rather than short quarter-mile stretches.
Available only in 1969 and 1970 as an engine option on a Mustang Sportsroof, Ford only made approximately 1,300 units of the Boss 429, making it a highly-desirable engine today.