When Jim Betz sets his mind on something, he does it in a big way. So, when he and his KSR Performance & Fabrication team decided to take a different route and assemble a 2015 Cadillac ATS for Ultra Street duty, the outcome absolutely exceeded expectations.

Always a fan of big horsepower and especially American muscle, Texas-born Betz helped his uncle, Lloyd “Hoss” Fowler, build a Ford Maverick in the early 1970s. Betz rebuilt his grandfather’s Dodge truck, too, and had fun wrenching on his own 1981 Chevy Camaro Z28.

Other than some sporadic small-town street racing on the weekends during his youth, though, the now 64-year-old didn’t have much track time in his life until his latter years. Instead, Betz spent several decades building and growing his commercial trucking company, Hard Drive Express.

“Racing was always a dream of mine, and I never thought it would come true,” shared the now-64-year-old man who turned that dream into a reality. He attended Frank Hawley’s Drag Racing School and earned his Super Comp license, then returned to obtain his Super Gas license as well. “In the late 2010s, I decided it was time. My business was in good hands with my son, William, running the day-to-day operations, and that allowed me to get away to race.”

Betz had a Ford Mustang Cobra Jet built and began competing in the now-defunct NMCA Factory Super Cars category in 2018. Jumping right into the fast and competitive class with his crew chief, Craig Spuhler, and car chief, Kim Mapes, Betz quickly learned the ropes and did quite well. It wasn’t long, however, before he felt the itch to go even faster.

In 2021, Betz and Spuhler were driving to dinner after the NHRA race in Gainesville, Florida. Talking about putting together a car for the now-defunct NMCA’s Extreme Street category, they decided they wanted something different from the traditional Mustang or Camaro. “We were in his [Craig’s] 2016 Cadillac ATS, and we both pretty much said at the same time, ‘what about something like this?’ and the ball started rolling,” recalled Betz.

Given that the ATS is built on the same platform as the sixth-generation Chevrolet Camaro, it was a pretty solid option. Betz wasted no time scouring dozens of online classified listings and finally found the perfect 2015 Cadillac ATS to use as a platform for his project.

What started as a clean, 21,000-mile used car in Obsession Red—and is still wearing its original paint today—has been transformed into the antithesis of stock. Mapes and his team at KSR (Kimco Shared Resources) in Carleton, Michigan, led the build from start to finish; they handled practically every piece and component in-house, from the engine build and machining to custom fabrication and more.

Under the OEM factory hood sits a 302 cubic inch Ford Coyote engine that’s been bumped up to 327 cubic inches with a 3.700” bore and 3.800” stroke. Inside the aluminum block, a Bryant crankshaft, CP pistons, and Carrillo connecting rods form the foundation of a monster.

With a high 14:1 compression ratio, titanium valves from Victory on both the intake and exhaust sides, and dual overhead cams custom spec’d by Chris Padgitt at Bullet Racing Cams, airflow through the factory Ford Voodoo cylinder heads (which were CNC’ed by Shaut Racing Heads) is rapid and relentless.

Fuel flows courtesy of a complete Aeromotive system and is delivered through a set of 170-pound/hour injectors. Finally, the engine’s dry sump oiling system, complete with a billet pan from Dailey Engineering, ensures critical components stay cool and lubricated while the Whipple supercharger brings a whopping 22 psi of boost to the party via a 150 mm throttle body.

After building and installing the engine—which is controlled by BigStuff’s advanced Gen4 Pro Xtreme total power management ECU and which utilizes a matching BigStuff ignition box, coil, and more. Mapes (who also tunes the system) and team fabricated the fantastic show-car-quality headers and zoomies.

“We’re using a Turbo 400 transmission from the experts at M&M Transmission, along with an M&M shifter, Meziere flywheel, and Neal Chance converter,” added Betz. Rounding out the driveline, a carbon fiber driveshaft from Mark Williams Enterprises was installed along with a 9” fabricated rear end, gears, and axles, all also from Mark Williams.

Handling suspension duties and helping the car launch as effectively as possible are Lamb shocks and springs at all four corners. Meanwhile, WELD wheels wrapped in Mickey Thompson’s quintessential ET Street radial tires grip the ground when Betz goes all in on the gas pedal.

Although the ATS still wears much of its original bodywork, and aside from some safety updates and racing gauges, the interior remains largely untouched. “It still looks like a Cadillac,” Betz laughed, “but it sure doesn’t act like one!”

The result of KSR’s hard work was a car that isn’t just fast, it’s bulletproof. “Kim did everything, and the result was exceptional,” Betz said. “I don’t have the skills to build such a great car and for it to be safe and correct, but I knew I wanted it done right, and Kim delivered.”

Betz’s beautiful Cadillac, which the guys christened “Madame X,” made its first public appearance at the NMCA season opener in Orlando, Florida, in March of 2023, but he graciously gifted Mapes with the opportunity to make its inaugural runs. At the time, Mapes hadn’t driven in more than a decade, and Betz had more fun just watching his friend have a blast instead—while gathering important feedback from the shakedown runs, of course.

After a successful debut, Betz slipped into the driver’s seat and continued campaigning his Cadillac under the flag of his Drive Hard Racing team. He ran it in NMCA’s Extreme Street class along with the NMRA’s Renegade category thanks to its Ford Coyote powerplant, but since the sanctioning bodies ceased operations in late 2024, his focus has shifted solely to Ultra Street.

“I’ve mostly been racing at Milan [now Darana] Dragway at their Heads Up events on the first Friday of every month,” shared Betz, who recently ran a personal best of 4.533 seconds at 157 mph with a 1.09-second 60-foot time in the eighth-mile. Making the run even more impressive was the fact that it was accomplished with a soft launch, and considering he had clocked a 1.07 short time previously, there are definitely a few numbers still left to shave off the timeslip.

And while Betz has quite a collection of “decent” cars at home—Fords, a Dodge Demon, a Viper TA, and a 2023 COPO—his Cadillac is truly a cut above. “The G’s it pulls at the line are something else,” said Betz, happily fulfilling his childhood fantasy. “It drives straight as an arrow, but it’s a crowd favorite, too.”

That sleeper look is part of the cool Caddy’s appeal. Spectators regularly crowd around the car at events, surprised to see a Cadillac lining up against the usual Fords and Chevys. “At every race, spectators take hundreds of photos,” he shared proudly. Although he jokes about not having been hands-on with the build, Betz has been deeply involved in every decision, from selecting the car to choosing the partners who made it happen. And, without those partners, the car wouldn’t be what it is today.

Even as he continues to fine-tune his unique Ultra Street “Madame X” 2015 Cadillac ATS, Betz is already looking forward: more testing, more racing, and maybe a few surprises down the road. “There’s a lot more left in this car, and a lot more I want to do with it,” he said. “It’s been a blast so far, and I can’t wait to see where it goes.”

For Jim Betz, this Cadillac is a big, bold statement that it’s never too late to build something wild, and a reminder that with the right team and the right vision, anything is possible—even turning an unconventional luxury sedan into a class-leading drag car.