Ford produced 859 Mustang Boss 429 units in 1969. The limited-production model was built to help homologate Ford’s powerful 429-cubic-inch V8 for NASCAR competition.
The Boss 429 was an unusually specialized Mustang. Its large engine could not fit into the standard engine compartment without extensive structural changes, so Ford sent partially completed cars to Kar Kraft. The company modified the front structure and installed the engine before the cars returned to the production process.
The 1969 cars used body-color hood scoops and black interiors, with five exterior colors available. Every example had a four-speed manual transmission. The car’s high cost, specialized construction, and low production volume made it far rarer than ordinary Mustangs of the same period.
The production figure is often confused with the combined total for both model years. Ford built another 499 Boss 429s in 1970, bringing original production for 1969–1970 to 1,358 or 1,359 depending on the historical source’s counting convention. For the 1969 model year alone, however, 859 is the standard trivia answer.