The Mustang Boss 429 has a really interesting story. When the car was produced by Ford in 1969, it was seen by those on the street as an instant disappointment.
In my opinion, the need and the purpose of this monster engine for Ford was completely different from the perception that potential buyers had of it. Make no mistake, Ford built this car for solely one reason; To outrun the Hemi engine on NASCAR tracks across America.
One of the most confusing things to enthusiasts of the day is that the engine was put in a Mustang – which was not NASCAR legal at the time – and not the fuller-sized Torino, which was a legal body style on the tracks at the time. In addition, Ford had to make an extra effort to get this behemoth engine to fit into a Mustang by having a company by the name of Kar Kraft in Brighton, Mich., shoehorn the power-plant into 859 Mustangs in 1969 and 499 Mustangs in 1970.
Incidentally, there are now said to be two 1969 Mercury Cougars that were released with the 429 engines. If you had one, their value today would be unbelievable. I have heard rumors that one of these Cougars currently resides in Indiana somewhere.
The Boss 429 engine when released in 1969 was conservatively rated at 375 horsepower in order to keep insurance companies somewhat happy. But the fact is that these cars were not tuned for the street, and in actuality were in the 500 horsepower range. In fact, I’m sure with a couple of tweaks, you could get close to 600.
The car, much like the Chrysler Hemis of the day, really didn’t like to idle or go slowly around town to get groceries and whatnot. Thus a lot of negative things were circulated about the Boss 429’s reliability. Drag racers were also disappointed in them, too, as they were looking for quick elapsed times. But again, that was not what the car was built for. So at stoplight races across America, the car got a bad reputation as being slow.
It shouldn’t have.
Once this car gets moving, it is an absolute beast. You do not want to tangle with this car; it’s been said that its top speed was around 175 mph – which was incredible in 1969 and is certainly no slouch today.
The value of these cars today hovers in the $300,000 to $400,000 range, depending on condition. Obviously they are quite rare, with only 1,358 being built between 1969 and ’70. None of these cars came with air conditioning because there wasn’t room under the hood for the unit. And of course none came with automatic transmissions.
These cars were special, though, and to emphasize that they were given specific NASCAR identifications that were placed on the driver’s side door. Each car built was given a “KK” number, which stood for Kar Kraft, with KK No. 1201 being the first in 1969 and KK No. 2558 being the last in 1970.
The cars used a single Holley four-barrel carburetor, although it is now believed there were two 1970 models with a dealer-installed option of a six-pack intake and carburetors.
To summarize, the Mustang Boss 429 was a misunderstood car when it was released and originally roamed the streets back in ’69 and ’70. But the car today is one of the most valuable in the muscle car world.