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Goals and passion are two things that go hand in hand in any form of serious sports, and in drag racing, they press racers to new heights — to go further and faster. Fulton, Mississippi native Jason Digby is a life-long adrenaline junkie that’s always had plenty of passion for racing and going fast on anything with wheels. With that drive, Digby has campaigned a number of stout rides, but his menacing nitrous-fed 1969 Dodge Dart feeds is his finest, terrorizing the popular Leaf Spring class category anywhere it shows up.
For Digby, his thirst for speed started at a young age with a desire to go fast on two wheels and grew from there. “My drag racing passion started when my parents agreed to co-sign a loan for a 1990 ZX-6 Kawasaki Ninja when I was 15 years old,” says Digby about his first racing machine.
His goal of going fast would not be denied, so to reach his objective he went to work. Literally. “I bought the ZX-6 by mowing about 20 yards in the summer, I was mowing yards before I could drive, so my mother would drop me off with my equipment and pick me up when I was finished.”
After all of his hard work, Digby was able to purchase the bike and grab a handful of throttle at the track.
“My parents agreed to let me take the bike the local drag strip in Fulton, which is owned by Mike and Carlton Franks, to see how fast I could go in a safe environment. I was hooked.” To help perfect his launching technique, a set of wheelie bars were bolted to his bike. He spent hours at a local abandoned airstrip practicing his craft. All of that practice was put to use, says Digby, as “we went every weekend to bracket race in the 1/8-mile drag bike classes.”
After a while, Digby and his family decided to add a couple more wheels to the equation and go door car racing, but the nitrous-huffing Dart wasn’t in the picture just yet. “We decided that we really wanted to build a drag car, so we bought a 1950 Chevy truck junker for $250 and got to work transforming it.” This was just the first incarnation of the truck, because as with every passion-filled race project, things escalated quickly.
“The truck started out as a Pro Street-type ride and eventually had a Funny Car-type fiberglass body and a decent small-block Chevy installed, and the rest is history. We’ve had the truck for over 20 years and my dad runs it in 6.0 index to this day.”
Digby still gets some seat time in his old ride, but says “I only wheel my old grocery-getter when dad wants to change to bigger jets, so I test pilot it for him,” he said.
Before acquiring the Dart, Digby’s power-based passion took a different turn, away from racing. “I got out of racing when I finished dental school in 1999 and ventured off into motorcycles again,” he says. At first, he started with a standard Harley Road King Classic, but his wife didn’t think the bike looked cool enough, so Digby cranked things up a few notches. “I ordered an Orange County Chopper Rigid Chopper before the show was ever on the air and rode it 2,700 miles in one year. I even ran it at the local drag strip.”
The bike was a real looker that won several shows, and even made it into a few magazines. But the need for speed came calling again for Digby, and he couldn’t resist. To get his Dart, a bit of wheeling and dealing had to take place first. “I traded a 1964 Chevelle Malibu Wagon bracket car, known as the ‘War Wagon’, to the one and only Kenny Ford about eight years ago. It was a running, driving, street car with a 340 cubic-inch engine and a 904 transmission. They still run the wagon out of the PTC camp to this day.”
I got out of racing when I finished dental school in 1999 and ventured off into motorcycles again.
The backbone of the Mopar bullet is a Jeff Burns Racing Engines-built Indy Maxx aluminum block that’s been punched out to 610 cubic inches with a 4.520-inch by 4.750-inch bore and stroke. Working inside the massive Mopar mill is a Callies crankshaft, Diamond Pistons, billet GRP connecting rods, and Comp Cams Elite lifters. The motor has a very healthy and nitrous-friendly 14:1 final compression ratio after all the parts are bolted into the block.
The top end of the motor is just as beefy as the bottom, with what’s described as “big” Bullet brand 55 mm solid roller camshaft that’s custom-built for this engine. Finish First Racing Heads worked over the aluminum Predator heads that are outfitted with Manley titanium intake and exhaust valves, PAC valve springs, and 1.8 ratio T&D rocker arms.
When running such an extreme setup, lubrication is paramount, and this engine is more than covered in that department. A Peterson R4 Dry Sump keeps the oil flowing through all of the 610 cubic inches, as it sucks the oil up from the custom Charlies Dry Sump oil pan that’s fitted with a windage tray and lower support.
The Indy Maxx based engine looks right at home under the hood of the Dart
If you’re going to run this many cubic inches and want to mix it with silly amounts of nitrous oxide, you’d better be sucking in a bunch of air, and Digby made sure this motor can move plenty of it. On top of the Predator heads is a cast Predator intake manifold with a custom billet top set up for twin throttle bodies. The dual Accufab 4500 throttle bodies move over 4000 cfm of air, combined to help the wicked Mopar engine breathe.
Big hits of nitrous require big throttle bodies.
Feeding all of the race gas into the throttle bodies is a fuel system that consists of Weldon fuel pump and regulator that’s matched to some massive Billet Atomizer injectors. Providing the spark is an MSD 7531 box and a MSD Front Drive distributor.
Giving the orders to the engine is a Big Stuff3 EFI box that has the dry nitrous upgrade loaded into it. Tuning duties for the engine are handled by Kevin Neal of Neal Performance Innovation. Digby tells us he recognizes how important Neal’s tuning skills are to his program. “Kevin never ceases to amaze me with his power management expertise in getting our car down the track,” he says.
Neal also provided the single-stage dry shot nitrous system on the car that Digby says is jetted up “enough” to put down over 1,200 horsepower to the Mickey Thompson drag radials out back. That’s been good enough to push the Dart to a best elapsed time of 4.56 and 155 mph in the 1/8-mile with a wicked 1.10 60-foot time.
To take the beating his nitrous motor hands out, Digby instituted a beefy two-speed Turbo Glide 400 transmission with a 1.48 first gear and Proformance Billet valve body built by Dave Klaput Proformance Transmission. The PTC torque converter 258 mm core and JW Billet flex plate help transfer the power to a Dynotech 4.5-inch aluminum driveshaft and the rest of the driveline.
Champion wheels help set the aggressive stance of the Mopar.
The 25.5 chromoly jungle gym in the Dart was fabricated by Mags Custom Chassis and is a total work of art. The front suspension consists of Heidts Mustang 2 control arms and Mark Menscer Motorsports AFCO coilover shocks with AFCO springs. A manual rack-and-pinion steering system helps keep the Dart running straight and true down the track.
The interior of the Dart is clean and to the point.
Eric Yost of Customs by Bigun of Mooresville, North Carolina performed the rear chassis upgrades over the winter to help the Dart hook harder. Out back rests a fabricated nine-inch chromoly Moser unit with a Strange Engineering Ultra Case and spool. Inside the rear end is a set of Moser gun-drilled 40-spline axles and 3.89 Motive gears. A set of Santhuff Leaf Spring Edition rear shocks are paired with Calvert Split Mono Leaf springs and rear sliders from Smith Racecraft Assassin Bars along with weld-on spring perches.
Digby insists that behind him is a great team to help keep the Dart rolling.
“There are two people that have been with me from the very beginning, starting with my good friend, Mag, who has done all the fabrication work on the car over the years. Also, Jeff Burns has been the mastermind behind both powerplants that have been in the car. New team members, Chad Branson and Lyle Barnett, who share the wheel, and Mark Barnett and Eric Yost, who made the old leaf spring car into a race car. And lastly, my dad, who has always supported my dreams.”
Digby focused his passion for anything fast, on any amount of wheels, to his goals of Leaf Spring domination. His Dart is ultra-clean, well-built, and uses all 610 cubic inches of its Mopar power to make some wicked-quick passes. Look for Digby’s Dart to shoot those big old nitrous-fed gorilla flames at a track near you very soon.
