Incredibly-rare 1969 Boss 429 Found in Florida, Mint & Drag-ready
Originally developed as a NASCAR homologation special, this rare Mustang may be the mightiest of them all.
Ford’s Mustang has been around for over half a century. Upon its release, it created an entirely new market segment – the pony car – and, in the ensuing years, became a legend.
Certain Mustangs are more legendary than others. Few will disagree when we say that the Boss 429 stands near the top of that illustrious list.
Fewer than 1,400 Boss 429s were built in 1969 and 1970 at the height of the muscle car horsepower wars. These big-cube pony cars were built to satisfy a NASCAR rule requiring that, for an engine to be legal for competition, at least 500 examples had to be built and sold to the public.
To fit the massive 429 cubic inch V8, the front end of the Mustang had to be substantially re-engineered. The cars were partially assembled at the Ford Rouge factory before being sent to Kar Kraft in nearby Brighton, Michigan. There, the cars were completed and sent to dealerships.
Compared to other Mustang performance trims, the Boss 429 was comparatively subdued, lacking the striping seen on Boss 302s and Mach 1s. Also subdued was the factory’s horsepower rating, which was tremendously underrated at just 375.
The Royal Maroon 1969 Boss 429 seen here is packing additional ponies under the hood. Offered for sale on Motorious, it allegedly spent most of its early life at the drag strip. While it may look like a stock Boss 429 at first glance, it’s packing some serious internal engine upgrades.
A stroker crank brings the total displacement of this elephantine powerplant to 521 cubic inches. A twin-carb intake manifold topped with a pair of 750 cfm four-barrel carbs replaces the single 735 cfm Holley carburetor.
Inside, you’ll find a four-point roll bar, and underneath, you’ll find in weld-in subframe connectors. Numerous suspension upgrades were installed, including a panhard bar. We recommend panhard bars for all solid axle Mustangs, and we’re glad to see one in use here.
No longer just a big motor with a pretty face, this living legend is an all-around improvement. Best of all, while the modifications may detract from the originality, they don’t detract from the understated looks of the Boss 429.