This is a 1969 Ford Mustang Fastback that has been given a comprehensive rebuild into what is now likely one of the fastest (and best handling) road-legal examples of its kind in the country.
The car has been given a full frame and a shock tower delete, it now rides on Heidts independent coilover front suspension and a Heidts 4-link rear end. Power is provided by a Kasse Boss 429 cubic inch 600 bhp V8 mated to a Tremec 5-speed manual transmission. This is considerably more than the 375 bhp produced by the original Boss 429 Mustang back in 1969.
Fast Facts – A 600 BHP 1969 Ford Mustang
- This 1969 Ford Mustang Fastback has undergone a complete rebuild, transforming it into a modern interpretation of the Boss 429. The car features a Heidts independent coilover front suspension, a Heidts 4-link rear end, and a Kasse Boss 429 600 bhp V8 engine paired with a Tremec 5-speed manual transmission.
- Originally not a Boss 429, this Mustang was rebuilt with significant modifications, including a full frame, deleted shock towers, and a new front suspension system to accommodate the large engine. The car also received four-wheel Wilwood disc brakes to handle the increased power from that 600 bhp V8.
- The Kasse Boss 429 V8 is equipped with custom cylinder heads, FAST fuel injection technology, and an Aeromotive Gen II Stealth fuel tank and pump. The car’s interior features custom touches, including bespoke black upholstery, a tilt steering column, air conditioning, and a Kenwood stereo system with Bluetooth.
- After its comprehensive rebuild, the car has only accumulated 500 miles and remains in like-new condition. It is now registered as “Boss 429” in Arizona and will be auctioned by Mecum on March 22, with details available for potential bidders.
The (Original) Boss 429 Mustang
The Boss 429 Mustang was Ford’s response to NASCAR’s homologation rules and is widely regarded as one of the most capable muscle cars of the late 1960s. Built exclusively for the 1969 and 1970 model years, the Boss 429 was designed to house Ford’s new 429 cubic inch (7.0 liter) semi-hemispherical V8, which was intended for NASCAR competition use. However, to comply with NASCAR’s requirement that a certain number of engines be installed in production cars, Ford turned to their Mustang lineup.
The car is now fitted with Dynacorn 17 inch Magnum 500 chrome wheels on all four corners in order to make room for the four-wheel Wilwood disc brakes.
The Mustang was chosen as the platform, but the engine was so large that significant modifications were required to make it fit. To handle this challenge, Ford turned to Kar Kraft, a specialty engineering firm based in Brighton, Michigan that often handled Ford motorsport work.
Kar Kraft extensively reworked the Mustang’s front end, modifying the shock towers and adjusting the front suspension to accommodate the 429’s dimensions. The battery was relocated to the trunk for better weight distribution, and the car was given a lower stance with a competition-ready suspension setup.arrangement.
The heart of the Boss 429 was its 429 cubic inch V8, featuring aluminum cylinder heads with a semi-hemispherical combustion chamber design, which led to its nickname, the “Blue Crescent” engine. Ford officially rated it at 375 bhp and 450 lb ft of torque, but many experts believe the actual output was well over 500 bhp.
Ford produced only 859 Boss 429 Mustangs in 1969 and just 499 in 1970, making it one of the rarest and most sought-after Mustangs ever built. Today, it remains a prized collector’s item, with pristine examples commanding well into six-figure prices at auction.
The 1969 Ford Mustang Fastback
The 1969 Ford Mustang you see here wasn’t a Boss 429 when it left the Ford factory new in the late 1960s, decades after this it would be given a comprehensive rebuilt to turn it into what some have described as a modern interpretation of a Boss 429.
Power is provided by a Kasse Boss 429 cubic inch 600 bhp V8 sending power back through a hydraulic clutch and a Tremec 5-speed manual transmission.
The car was taken back to a bare shell, and a full frame was added. The original shock towers were deleted to help make room for the gargantuan engine, and a completely new front suspension system was installed Heidts independent coilover arrangement. This was paired in the rear with a Heidts 4-link rear end.
Four wheel Wilwood disc brakes were also fitted, they were deemed necessary given the fact that a Kasse Boss 429 cubic inch 600 bhp V8 had been ordered. Once this engine was installed it was mated to a hydraulic clutch and a Tremec 5-speed manual transmission.
The engine was topped with FAST fuel/air spark technology fuel-injection with velocity stacks, custom cylinder heads, and a serpentine drive belt system. Fuel is provided by an Aeromotive Gen II Stealth fuel tank and pump.
It was given Lizard Skin sound deadening and custom jet black gloss paint over a black interior, with Dynacorn 17 inch Magnum 500 chrome wheels on all four corners.
The car has electric locks and windows, an Ididit tilt steering column, power steering, a Kenwood four-speaker amp stereo system with Bluetooth, Old Air Products Hurricane heat and air conditioning and heat, and a custom interior including seats, console, and headliner.
The interior features Old Air Products Hurricane heat and air conditioning and heat, a Kenwood four-speaker amp stereo system, electric locks and windows, and custom upholstery.
Since the build was completed the car has accumulated just 500 or so miles on the odometer, meaning it’s still in almost-new condition throughout. It currently carries the Arizona registration “Boss 429” which seems fitting.
It’s now due to roll across the auction block with Mecum on the 22nd of March. If you’d like to read more about it or place a bid you can visit the listing here.
Images courtesy of Mecum
Articles that Ben has written have been covered on CNN, Popular Mechanics, Smithsonian Magazine, Road & Track Magazine, the official Pinterest blog, the official eBay Motors blog, BuzzFeed, Autoweek Magazine, Wired Magazine, Autoblog, Gear Patrol, Jalopnik, The Verge, and many more.
Silodrome was founded by Ben back in 2010, in the years since the site has grown to become a world leader in the alternative and vintage motoring sector, with well over a million monthly readers from around the world and many hundreds of thousands of followers on social media.
