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Resurrected! Carl Holbrook’s Old Super Stock 1969 Mustang 428 Cobra Jet!
Captain Cobra Jet’s fantastic journey
Some Super Stockers have a rough life. They’re constantly being worked on and cut up to remain competitive in their respective class. When new rules come about, they get updated to stay legal, but to some drivers, they’re just a chapter in their racing career. There’s always a better mousetrap to be built with more advantageous engine and chassis combinations.
When Ford “Flogger” and FE guru Carl Holbrook set out to build this Mustang convertible Super Stocker in the mid ’70s, he was looking at which combination would have a favorable weight break and horsepower factor. Having vast knowledge of the Ford FE engine, Carl had the know-how to make them killer pieces that would be class winners. He started a successful engine-building business back in the ’70s, and that legacy was passed on to his son Chris, who also races and builds some very fast current-generation Cobra Jet Stockers and Super Stockers.
Starting out way back when, Carl Holbrook had been running a 1969 428 Mustang fastback in Super Stock, but wanted to build something different during the ’70s as NHRA started to loosen up the class rules. Carl quickly earned the nickname “Captain Cobra Jet,” as one who could take a mild 428 (or even a 390) and turn it into a fire-breathing monster that could slay 396 Chevys, and even a 440 Mopars.
Or click here to download and view a section of the September 1975 issue of Hot Rod on Holbrook’s 428 CJ Mustang
Carl quickly determined a 428 Cobra Jet in a 1969 Mustang convertible would be a great combination to build for the SS/HA and SS/GA classes. The 428 CJ is quite the torque monster and would make tons of power, while the ragtop body would have a much better 50/50 weight distribution advantage over the other cars in the class.
Holbrook also incorporated into the Mustang Super Stocker an innovative feature for the time—a four-link suspension. Carl, along with Tom Smith at Wolverine Chassis in Romulus, Michigan, used this technology when building the Mustang. This was Carl’s first foray in using a four-link in a Super Stocker, and he learned quickly how to dial-in the rear suspension for various track conditions.
With a NHRA Super Stock-legal 428 Cobra Jet under the hood, the soft-top pony was able to click off consistent 10.80 passes at more than 125mph, while weighing a chunky 3,434 pounds. Remember, this was at a time when Super Stockers were running basically cast aluminum intake manifolds, not today’s sculptured sheetmetal pieces. Also, cylinder head and camshaft technology in Super Stock was still learning to walk and evolving.
But, it was Holbrook’s attention to detail and the 428 CJ Mustang’s stellar performance with wheels-up launches that got the attention of then Hot Rod editor Terry Cook, who was so enamored that a low-dollar Ford racer like Carl Holbrook could make just as much power as the big-name Ford racers, and hence did a story on it. It was this article that captivated a fledgling Michigan Ford enthusiast, Bob Reynolds. But, we’ll get back to that in a moment.
Even before he started flipping through the pages of Hot Rod magazine, Bob was already banging gears in the summer of 1970 in a red 1969 Mach1 with a 428 CJ huddled under the Shaker hood. Bob, who was only 17 and still in high school, pooled the money he earned from working on a farm and a grocery store to purchase the barely broken-in Mach1 that he spotted in the front row of the used car lot of one of the biggest high-performance dealers of the era, Berger Chevrolet in Grand Rapids, Michigan.
Bob pulled over to check out the Mustang, opened the door, and sat in those high bucket seats. The salesman tossed him the keys to fire up the Mach1 and seeing the Shaker dancing as the 428 CJ was warming up was all it took for Bob to sign on the dotted line for the sum of $2,695.
Rowing that Hurst shifter with that big 428 attached set the die for young Bob, as he and his Mach1 became quite notorious around the streets of Lowell, Michigan. Bob wanted to know how to make the CJ run better and was an avid reader of all the performance publications back in the day, such as Super Stock and Drag Illustrated, Car Craft, and Hot Rod, looking for any articles on modifying the 428 CJ while he was actively racing the Mustang. When the September 1975 issue of Hot Rod came out, Terry Cook did a deep dive on Holbrook’s 428 Super Stock engine and that really got Bob’s attention. He was intrigued by Carl Holbrook’s ability to make the highly underrated 428, which was originally born to power Thunderbirds, Galaxie 500s, and Country Squire wagons, run head-to-head with more exotic Chrysler and GM machinery. Bob was impressed that the Mustang convertible left the starting line with the front dangling in the air.
Bob hung on to that issue of Hot Rod as his family moved from Michigan to Montana. He was not pleased with the move to Montana. He was more interested in bolting go-fast parts onto his Mustang than corralling them. It also took him away from his car club buddies, who he spent many hours with cruising and racing at U.S. 131 Dragway in Martin.
In 1978, Bob headed to Montana’s only drag strip at the time, over in Lewiston. The track was running a Stock/Super Stock combo race, and it was there Bob noticed a 428CJ Mustang convertible running in Super Stock. He was all over the car and when he finally met the owner, John Gass, he asked him immediately about the Mustang’s racing background.
That’s when John informed Bob that he had purchased the Super Stocker two years prior from Carl Holbrook in Michigan. Bob instantly lit up, knowing this was the same car from the Hot Rod article that he clung onto for many years. Imagining what was going through Bob’s mind, here’s the car that inspired him to race and build up his Mach1 right in front of him. When John mentioned he was selling the ex-Holbrook Super Stocker, Bob quickly jumped on it and a deal was struck to purchase the former NHRA record-holding Mustang Cobra Jet for $5,500.
Bob, who was now 25, immediately got in touch with Carl Holbrook to let him know he had his old Mustang Super Stocker racecar and wanted to know if he could offer some assistance. Carl instantly gave some support and tuning tips to keep the 428 CJ competitive, which evolved into a few 1,500-mile journeys with the car in tow from Montana to Holbrook’s shop in Livonia, Michigan. Carl did a great deal of development work on Bob’s 428 and updated the suspension.
Bob got the car running, and in the late ’70s, did some class racing. But when Bob’s local track adopted a bracket-racing format and killed off their weekly Stock and Super Stock programs, he felt it was time to park the Mustang. It was the right decision for the time, as family, work, running a business, and other priorities were now a part of Bob’s daily life.
In 2003, Yellowstone Drag Strip opened up near Billings, Montana. Being an NHRA track, they host a Division event that incudes Stock and Super Stock. That’s all Bob needed to motivate him to resurrect the Mustang convertible Super Stocker and get it going again. The progress has been slow, but steady for Bob, who’s now 63 years old. He’s had the help of longtime 428 Cobra Jet Super Stock racer, Gene McBean, to bring him up to speed on new parts and technology. Gene prepped both the 428CJ and the C6 trans for Bob.
We got to meet Bob and Gene last month at the NHRA North Central Division season opener at Indianapolis Raceway Park. That weekend was the culmination of the hard work both of them have put into getting Bob’s 428CJ Mustang convertible Super Stocker dialed in. There are more bugs to work out, but Bob and the Mustang broke into the nines for the first time ever by qualifying with a 9.95 and 9.94 in SS/FA.
Bob is happy knowing that Carl Holbrook, who passed away in 2000, is smiling down on him knowing that his old 428CJ Super Stock Mustang convertible is still being flogged.