Ford fans were a bit perturbed when the COPO Camaro arrived with the Corvette’s 427 V8. So they demanded Dearborn build an answer. The only logical choice was to use the same formula. Stuff the largest engine they ever built into the Mustang. The only problem is that the Boss 429 V8 is a monster.
It is so tall and wide that it could not be installed on the assembly line. So Mustang engineers turned to a custom shop to make it work. Kar Kraft is closer to Ann Arbor than they are to Dearborn but they were the only ones who could figure it out. The Mustang is a unibody, so the shock towers are composed of sheet metal with braces to the firewall. Every inch of this structure was consumed by the 429, so they built a new front suspension that is unique to the Boss 429.
To keep some notion of balance, a new firewall was needed to mount the engine further back than a small block. The 429 was nearly 300 lbs heavier than a small block 302, so many other areas were reinforced. These changes essentially made it a new car wearing the same body as a standard 1969 Mustang. Of course, they needed to make sure it could handle the 425 horsepower and 460 lb-ft of torque. Who were they kidding? This was a race motor, so the modest output ratings were for insurance reasons.
Five prototypes were built, and they were slightly overpowered. Naturally, the first car was crash tested to meet DOT approval. The second prototype (KK1213) is seen above, and it needs to be part of your collection. It only has 871.9 original miles, because everyone knows it is the earliest Boss 429 in existence. Dave Lyall was a Super Stock racer, and also worked for Ford in Livonia, Michigan. This was the height of the Super Stock era, as manufacturers poured massive time and engineering to turn the fastest ET.
The Boss 429 had two flavors of Hemi, and Dave chose the Shotgun Hemi. Essentially a NASCAR engine, it allowed Dave to make the first 9-second pass in AHRA Super Stock at the Briston Spring Nationals. As Super Stock racers evolved into Pro Stock, Dave sold the car to Gary Horton of Canton, Ohio. He ran the car in Pro Stock and B/Gas under the name Shotgun Express. His best time was 9.23 @ 152 in 1977. Thankfully he chose to park it for posterity.
By the late 80’s the Super Stock racers were growing nostalgic for the old days, so Shotgun was back at the track. Running against the likes of Farmer Bestwick and others, Ford Motorsport approached him to consider restoring it to its 1969 condition. As one of only a handful of Factory-backed lightweight Boss 429’s he agreed it should be restored. Although it had lived at the track for most of its life, much of the original hardware just needed cleaning up. The drum brakes, Cragar wheels, steering wheel were the same parts from the assembly line. Even the hood scoop was part of Ford’s race package, but the Stroud Parachute was an essential upgrade in the 70s.
He took great care in repainting the graphics of Dave’s company: Custom Speed Enterprises. Some of the car’s fastest times were thanks to Jack Roush’s engine tuning, but he was busy running his NASCAR empire. So Gary turned to Canton Auto Machine Service for a complete rebuild. Starting with 12.5:1 forged Wiseco pistons, they turned to Crower for a monster roller cam. It is a .690/.681 lift with 317/331 duration.
While it might seem extreme, Gary’s son Chris works for a Nitro drag team and they verified those specs as being original to Ford’s Super Stock Shotgun 429. Although it was a 4-speed for many years, a JW 3-speed automatic was used to keep this valuable 429 out of danger. It packs a 5,500 converter that sends power to 4.56 gears. So is it a museum piece? Without a doubt. But it does not collect dust, because once the restoration was complete it went 9.90 at Frank Spittle’s Super Stock Reunion.
It earned 986 out of 1,000 points at the Muscle Car Nationals, and it has a fully documented history. It is the best-preserved survivor that witnessed the end of Super Stock and the birth of Pro Stock. Sure there are a few Boss 429s left, but not factory backed lightweight drag cars. Mustang 360 did an in-depth feature, which is also included. Click the link below for all the details, and crank up your volume for the video!
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