In 1969 the Nascar wars were in full effect. GM was not really in the game, but Mopar and Ford were going at it. The 1968 season had shown just how aero the new Torino was. But Ford was still overmatched by the Hemi. Nascar would not allow Ford to run the 427 Cammer so they had a new motor, the Boss 429. In order for the engine to be legal in Nascar, Ford need to sell 500 to the public. Initially the motor was to go in to the Talladega but Ford decided the Boss 429 Mustang was the best place for it to be sold. Still Ford knew that to be competitive on the Super Speedways they needed a more aerodynamic car. They engineered a more slippery nose on the front end moving the grille flush the rest of the front. The bumper was a rear bumper cut and rewelded to fit the front. The biggest change was the rockers were rolled. This allowed Ford to lower the car more than a stock Torino for racing yet still be within Nascar regulations.
As great as the Boss 429's reputation is, those that experienced it know it wasn't a very good street motor in the Mustang. That's because it's original mission was for the big oval, not the local drag strips. There were something like 750 Talladega's total, including some prototypes. Plenty of them were trashed as race cars, but some pristine examples still exist.