| The Boss 429 Mustang was introduced in 1969 to | | | | the NASCAR oval track racing. Ford has to qualify |
| memorialize the 420 Boss engine that was used | | | | the engine and the only way they were going to |
| by NASCAR. The car had to be designed to fit | | | | accomplish this was by making a few production |
| around the size and the power of the engine and | | | | cars that used it. Many people would be surprised |
| no one was more qualified to do this then Ford. All | | | | to know that the street model of the Boss 429 |
| of the parts came from Ford's assembly plant but | | | | did not share any parts with the Boss 429 Hemi |
| were given to Kar Kraft - an outside contractor - | | | | that was used during the races. |
| to modify them. | | | | Many of the later models were equipped with a |
| Ford was forced to move the battery down to | | | | solid lifter camshaft. This was different from what |
| the trunk so as to make more room for the | | | | was used in the earlier models because it offered |
| engine underneath the hood. This was ideal in | | | | more lift. However, they were not given enough |
| more ways then one. It was able to | | | | time in production and greatly affected the way in |
| counterbalance the weight of the car - which for | | | | which people were able to drive it. |
| many people made it easier for them to drag | | | | The most defining feature of the Boss 429 |
| race. They used a battery cap vent kit to help | | | | Mustang is the front spoiler. This is different from |
| vent fumes outside of the trunk through a rubber | | | | what was used on the MACH-1 and Boss 302 |
| hose. | | | | models. It is shorter so as to give the car more |
| This particular Mustang model was designed to | | | | curb clearance due to the low front end it was |
| compete against the Chrysler 426 Hemi during | | | | designed with. |