Donald Farr
Former Editor, Mustang Monthly
December 15, 2009
Photos By: Jerry Heasley

Mason Jones has a thing for '70 Mustangs with white interiors, having put together quite a collection of '70 Boss 429s. All four have white interiors, making his Grabber Green, Grabber Orange, Calypso Coral, and Pastel Blue Bosses among the rarest of the Boss 429 Mustangs. So it comes as no surprise that Mason took special notice of the pair of Quarter Horse prototypes built by Kar Kraft in 1969 as a possible replacement for both the Shelby and Boss 429. Both Quarter Horses, one in Candyapple Red and the other in Grabber Blue, had white interiors.

"I learned about the Quarter Horses through magazine articles back when I was in high school and college," Mason says. "I've always thought they were such neat cars and it was a shame Ford never built them. I started thinking about them again when Steve Strange devoted a page to them in his Boss 429 book. But when I saw one of the original cars on display at the Carlisle All-Ford Nationals in 2005, I decided it was time to build my own version."

Although both of the original Quarter Horses survive today in the hands of collectors, Mason wanted something even more unique. In addition to his infatuation with the white-interior, Shelby-look Quarter Horses, he's always wanted a car powered by one of the legendary 427 Single-Overhead Cam engines. "I've always wanted to put a 427 Cammer into a cool car," Mason explains. "So why not build a Cammer Quarter Horse?"

The project came together from two separate angles-one for the car and the other for the rare 427 SOHC engine. The body, a rust-free '70 fastback (with white interior, of course) that Mason acquired as part of a Boss 429 trade, was put in the capable hands of Martin Euler, who handles Mason's Boss 429 restorations at his Euler Restorations shop in Midland, Michigan. That was the easy part. Finding a 427 Cammer, preferably one of the newer all-aluminum versions, would prove more challenging.

"Somehow, Martin found out about Rick Toombs," says Mason. "Rick built engines at Holman-Moody when he was younger. When Martin contacted Rick, he was already trying to locate some aluminum Cammer motors for a couple of drag race engines. So I sent him a bunch of money and he started finding and buying the parts, sometimes from as far away as California or Australia."

Those parts included an aluminum 427 block from Robert Pond Motorsport, aluminum SOHC heads, Eagle crank with Diamond forged pistons, and a pair of custom Holley carburetors. With high-rpm, high-horsepower capabilities, Mason had to decide how much power he wanted Toombs to build into the special engine. "He was building two race Cammers with 1,200 hp," Mason told us. "I didn't want to go down that road for a street car. So he calmed it down to around 825-850 hp. The rev limiter was originally set for 8,000 rpm, but I think we're going to settle in at around 7,000. We're trying to keep this thing where it won't tear the Mustang apart."

Keeping the Mustang together was Martin Euler's responsibility as he constructed the chassis and body. First, he replicated Boss 429 shock towers to make room for the massive Cammer, which measures an inch wider than a Boss 429. Then he added a 2x4 steel tube brace inside the rocker panels, similar to convertible braces but stronger, and welded the '69-'70 Shelby roll bar to them. A Total Control X-style connector ties the front and rear subframes together.

The suspension is also from Total Control, including the upper and lower front control arms, rack-and-pinion steering, and G-Link rear suspension that replaces the factory leaf springs with coilover shocks. Brakes are discs all around utilizing 13-inch rotors and three-piston calipers from Stainless Steel Brakes Corporation.

To get the Quarter Horse look, Martin acquired aftermarket '69-'70 Shelby front end fiberglass and chrome trim from Tony Branda Performance. He filled in the scoop openings, as used on the original Quarter Horse prototypes, but had to fabricate a raised center scoop, shaped similar to the '69-'70 Shelby scoop, to clear the twin Holley four-barrels on the Cammer engine. "Martin tried several Boss-style scoops," Mason says, "but we really didn't want it to look like a Boss 429. So we tried the best we could to make it look more like the original Quarter Horse hoods."

At first, Mason wanted to paint the car in yellow, but he changed his mind mid-stream. "Martin had actually started painting the front of the car in Competition Yellow," Mason says. "He showed me a couple of pictures and I just changed my mind, thinking that Competition Orange would just blow people away. I'm glad we did it."

The wheels are 17x8-inch American Racing with 245/40x17 Pilot Sport tires. "We tried to get as much meat under there as possible," Mason reports, "but with a Mustang you run out of tire room pretty quick."

Inside, Don's Upholstery in Sanford, Michigan, took the white Deluxe upholstery and customized it with unique Quarter Horse embroidery and orange piping. For a classier look, the fiberglass rear trim panels are covered in white vinyl. For the instrument panel, Martin modified a factory cluster so he could install white-face AutoMeter gauges.

With the Boss 429 shock towers, the 427 Cammer dropped right into place. Despite its massive size, Martin says the all-aluminum engine weighs just 490 pounds, about the same as a standard production 351 Windsor. However, Martin admits there were plenty of challenges. Mason wanted power brakes, so Martin ended up creating a wedge to position the booster and master cylinder away from the valve cover, a change that also forced Martin to modify the clutch linkage. Mason also requested air conditioning, something never even considered for vintage SOHCs, but Martin was able to fabricate the brackets needed to mount an A/C compressor to the big engine. Headers were fabricated for the Cammer in a Mustang chassis and connected to Flowmaster mufflers.

More fabrication was required for the transmission crossmember. "I race Vipers on the side so I wanted a Viper heavy-duty Tremec T-56 six-speed," Mason says. "I've never seen one of them break. It's a little different and a little stronger than the T-56 used in new Shelby GT500s." The rearend is a 9-inch with 3.50 gears.

After three years of planning, searching for parts, and fabricating, Mason's Cammer Quarter Horse was completed just in time to debut at last year's Mid America Ford and Team Shelby Nationals in Tulsa. But, of course, there were bugs to iron out. "That motor is nuts," Mason says. "The first time Martin drove the car, he tore out the universal joints-and he wasn't even getting on it hard."

At Tulsa, issues also surfaced with the engine tappets, so Martin ended up pulling the engine and taking it back to Toombs for a top-end overhaul with stronger lifters from Keith Craft. But Mason hopes all of the struggles and challenges will help others in the future. "Hopefully, people who want to put Cammer engines together in the future won't have as many problems," he says. "Those nagging problems are just some of the things you have to deal with when putting together a legend."

The Original Quarter Horses
In late 1969, the "Composite Mustang," as it was called at Ford, was among a number of projects being developed by Kar Kraft, Ford's special performance engineering contractor and Boss 429 assembly line located in Brighton, Michigan. Also known as the Quarter Horse, two cars were constructed as a possible mid-'70 replacement for the Shelby and Boss 429 Mustangs. Built on '70 Boss 429 chassis with Shelby-style front-end fiberglass and a Cougar instrument panel, it's easy to see how the prototypes earned their in-house "composite" description.

As Boss 429s, both cars had the special inner fenders for the larger Boss 429 engine. The Grabber Blue prototype even had a Boss 429 number, KK2061, although the car was eventually equipped with a 429 SCJ engine. Ford later provided the car to a TV studio for the 1971 detective series Dan August, starring Burt Reynolds. Today the car is owned by Randy Woods. Many of our readers saw it at the Boss Nationals during the Carlisle All-Ford Nationals in 2005.

The Candyapple Red Quarter Horse was also fitted with a 429 SCJ engine. According to Steve Strange's book, Boss 429: Performance Mustang Style, the red Quarter Horse was used for performance tests and evaluations, running high 13-second quarter-miles at 103 mph. Today, the red Quarter Horse is owned by Christopher Lemp, who recently delivered the car to Don Goebel at Goebel's Performance Corner Restorations for a complete restoration in the near future.