1970 Ford Mustang

"Boss 429"


Configuration: Longitudinal front engine

Engine: V8

Displacement: 429 cid/7.03L

Horsepower: 375hp at 5,200RPM

Torque: 450 ft-lbs at 3,400RPM

Transmission: 4-speed manual

A Little History

This Boss 429 engine was specifically made to compete in NASCAR racing. The rules stated that at least 500 regular-production models had to be available for sale to the public, but they had a small loophole that proved very convenient for Ford. The rules did not state that the regular-production model body and engine be built together, which allowed Ford to advertise and sell the Boss 429 engine in the Mach 1 body, but race it in the Ford Torino Talledega body.

For the street-legal models, 1,358 total 1969 Mustang bodies were delivered to the Kar Kraft factory in December of 1968 where they were promptly stripped of their engines and given reinforced engine chambers with extra space. They were given either a “T-code” engine or an “A-code” engine, the latter being far more rare with revised smog controls, then sent out for sale as  the new 1970 Ford Mustang Boss 429.

Surprisingly, the reviews of the car were actually mixed. The engine and build had the potential to be the best muscle car ever made, but its efforts were thwarted right at the peak of engine performance because of needing to make the car street-legal. Critics never felt that the Boss 429 did as well as it was capable of doing based on the hype that initially surrounded it.

Did You Know?

  • The Boss 429 engine was nicknamed “Semi-Hemi” because of the revised combustion chambers that weren’t quite hemispherical.
  • Of the 1,358 Boss 429s produced in 1970, the car on display is 1 of only 12 to have left the factory in the Grabber Green color.
  • It was sold for $4,798 in 1969 with no additional options added.
  • Both the Boss 429 and the Boss 302 model, also on display, were replaced by the 1971 Boss 351. The 429 became a factory-option what was altogether abandoned by 1972.

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