One of the wildest cars at this year’s Sick Week drag-and-drive event — and at any race that its owner, Danny Humphreys, rolls it into — is this one-of-a-kind, screw-supercharged 1978 Porsche 928. With a Whipple supercharger seemingly as large as the German-made sports car itself, the bright blue Porsche turns heads, whether cruising down the highway or turning 6-second-capable performances on the strip.

Humphreys, from Midlothian, Texas, is an insurance agent by profession but a racer by passion. For Danny, engines and the thrill of speed have been integral parts of his life since 1984. Over the years, he has built, raced, and modified an array of cars, each one pushing the boundaries of speed and performance. His current pride and joy is a 1978 Porsche 928, an automotive marvel that has seen nearly two decades of evolution, evolving into a drag-and-drive car capable of thousands of miles of highway and dragstrip abuse, all in the same week.

A Racing Legacy

Humphreys’ journey into racing is as enigmatic as it is inspiring. “I have no idea how I got into racing because no one in my family had any automotive background,” he says. It was a self-made path that began with a 1977 Nova equipped with a big block, transitioning through a series of ever more powerful and complex vehicles. His early exploits in street racing gave way to more formal competitions, including a notable stint with a 1977 Vega running Top Sportsman, achieving a best e.t. of 7.60 in the 1/4-mile.

After a hiatus to focus on family and business, Danny set out to return to the track with renewed vigor. He bought the Porsche 928 in 2001, a car that would become central to his racing endeavors. The initial configuration featured a 540 pump gas nitrous combo, but this was just the beginning. Over the years, the Porsche underwent multiple transformations, each iteration producing more power and speed. From a 557 blown big-block to the current 572 cubic inch SMX engine built by Steve Morris, the Porsche 928 has gone from mild to purely wild, in both performance and looks.

The Build: A Labor of Love

The journey to transform the Porsche 928 into a drag-and-drive beast was neither quick nor straightforward. “It took me quite a while to get everything done,” Danny reflects. “Life happened.” Purchased in 2001, the car was immediately stripped of its original Porsche engine. Danny backhalved the chassis and installed the 540 pump gas nitrous engine. This setup was short-lived as Danny aimed higher, completely gutting the car and redoing the chassis to accommodate the 557 blown big-block for Outlaw 10.5 competitions.

Around 2004, the car went into storage, a period of dormancy that lasted nearly a decade. During that time, he briefly campaigned a C7 Corvette with a blown Hemi, winning numerous races and setting records. 

When Danny sold the Corvette and finally dusted off the Porsche, he was determined to turn it back into a street car. This phase saw the installation of a pump gas blown big-block, but even this wasn’t enough. “It just wasn’t enough power,” Danny admits. The final evolution came with the installation of a 572 cubic inch SMX engine from Steve Morris, a move that signaled Danny’s full commitment to the drag-and-drive format. While the engine was being built, Danny tore the car apart and installed a new 4-link and rearend, and replumbed and rewired entire car.

All The Boost

Danny’s Porsche is an impressive blend of power, precision, and pure insanity. The engine, a 572 cubic inch SMX, boasts a compression ratio of 10:1, with a billet SMX block and a Bryant billet crankshaft. The connecting rods are MGP, while the pistons come from Diamond. A Bullet camshaft, titanium valves, and Manton rocker arms, pushrods, and springs complete the engine’s valvetrain.

The induction system is a standout feature, utilizing a tall JDF F6 Inductor Injector hat paired with a Whipple R980 screw blower. This combination, along with the custom headers and exhaust fabricated by Danny himself, ensures the car delivers in the performance department. Ignition is managed by an MSD Pro 600, while fuel is supplied by an Aeromotive mechanical pump featuring System 1 filters and ComSync injectors ensuring optimal flow. A wet sump oiling system is likewise paired with System 1 pump and filters. The combination is managed by a Holley EFI system, and also sports a Davis Profiler EFI module.

The drivetrain is equally impressive, featuring a Rossler two-speed Turbo 400 transmission and a Coan billet aluminum torque converter, with a Gear Vendors overdrive unit. The rearend comprises a Strange Modular 9-inch housing, a billet Strange third member with 10-inch, 3.70 gears, and Strange floaters. The braking system includes Wilwood discs at the front and Strange discs at the rear, providing the stopping power necessary for a car of this caliber.

The modified stock front suspension features AFCO shocks and Bogart 3.5- x 15-inch Hoosier tires, while the rear suspension setup from Kenny Hubbard boasts either RC Comp 15- x 10-inch wheels with 8-inch radials, or Bogart 15- x 15-inch wheels with Hoosier Quick Time Pro big slicks.

Continued Evolution

One of the most remarkable aspects of Danny’s Porsche 928 is the level of personal involvement in its build. “I do all the work on the car myself — chassis, plumbing, wiring, carbon-fiber, and so on. Other than paint, engine, and transmission, it’s all me,” Danny states proudly. The car features a mild steel backhalf chassis with double framerails from the firewall back. Danny is currently working on a new 25.2 4130 chassis, showcasing his dedication to improvement.

The body retains its factory panels, with the exception of a carbon-fiber front bumper and hood. Painted in Dodge Viper Blue, the car stands out not just for its performance but also for its striking appearance. Inside, the Porsche features custom carbon-fiber with welded steel floors and Kirkey seats.

Aiming for the Finish Line

For Danny, the ultimate goal with his Porsche 928 is clear: “I want to finish a drag-and-drive. I feel like the car is fast enough to compete. I have attempted two events, but wasn’t able to finish either.” Despite these setbacks, Danny remains undeterred. His best e.t. is an impressive 4.46 seconds at 168 mph in the 1/8-mile, and he is aiming for even more ambitious targets—running 6-second times at over 200 mph to the 1/4-mile.

Danny’s journey with his Porsche 928 isn’t just about speed and records. It’s about passion and the joy of seeing people’s reactions when they encounter his unique creation. “I love people’s reaction when they see the car — it’s pretty ridiculous and stands out in a crowd,” he says.

In 2022, the Porsche was selected as a top 10 finalist in the Hot Wheels Legends car show in Dallas, an achievement that led Danny to Jay Leno’s shop for the final judgment. “We didn’t win, but it was a great experience,” Danny recounts.

I’ve always run a Whipple supercharger on this car, and I’d have to say it’s definitely the focal point with the JDF F6 Inductor injector hat finishing things off.

Humphrey competes locally in Texas at Xtreme Raceway Park in Ferris, and will continue to campaign in drag and drive events nationally.

Danny continues to fine-tune his Porsche 928, refining the combination all with a goal of quicker and faster runs, consistency, and reliability, all with a vision of success in the drag-and-drive racing world.