Top 20 Muscle Cars of All Time

8. 1969 Ford Boss 429

The Ford Boss 429 (also known as the Boss 9) is likely one of the rarest and most valuable muscle cars to date. In total there were only 1358 Boss 429s made. The origin of the Boss 429 was the result of Ford trying to develop an engine that could compete with the Chrysler 426 Hemi. NASCAR rules required that at least 500 cars be fitted with the new motor and sold to the public before it would be allowed to race. The engine was derived from the Ford 385 Engine, using four bolt mains, a forged steel crank and connecting rods. After the engine was designed, the Mustang’s body needed to be modified to fit the motor, as the motor was too wide for the current Mustang body. While the 429 Boss was rated at 375 horsepower, actual output was well over 500 horsepower, with some claims that it made 600 or more.