How A Mad Genius Welded An Old Dodge Truck Onto A 505 HP Ram SRT-10, Got It Through German Inspection

There’s something special about old trucks. Maybe it’s the patina, how every scratch and dent is part of a grand story. Maybe it’s the comfy seats or the classic aesthetic reminder of years gone by. There’s only one thing they’re missing—big power. But if you’re talented and dedicated, there’s a lot you can do about that.

Meet Johann Rauch. He’s a passionate car enthusiast from Kleinwallstadt, Germany, and the crew chief behind a monstrous Corvette dragster with a 14-liter engine and a four stage nitrous system. That alone would give us plenty to talk about, but there’s another project of his that caught our fascination.

At a glance, you might think you’re looking at a humble Dodge D100, cruising its way along German roads. Only, the wheels are too large… and the engine note is far too deep and raucous. These are mere hints at the V10 secret lurking beneath.

“This is a swap I did in my shop back in 2018 in Germany,” Johann tells me. “A lot of people claimed they did this, but I’m the only one that can show you the steps of the [buid] in my shop.” The inspiration for the build was simple. “A friend of mine asked if this is legally possible in Germany… he loved his Ram SRT10, but always preferred old cars,” Johann explains. Thus, the idea was born—to give a classic D100 the power of the Viper’s V10.

“Finding the D100 was a coincidence. My friend found it on a local ad in the newspaper, ” says Johann.  “Ugly as hell, but he liked the original used look.” The ratty patina is completely legitimate, he assures us. “Many trucks are just painted to look old, but this was someone’s work truck,” he explains.

The build has been credited to many shops over the years, but the true story of its creation lies with Johann. “It was featured in some car magazines here in Germany, and many companies claimed they‘ve done the swap, and I was never mentioned,” he says. “Of course they don’t have pictures from the [build] steps, it’s just now that I put them on the Internet.” As always, the proof is in the process.

The 2006 Ram SRT10 donor vehicle was factory fitted with the 8.3-liter V10 engine from the Dodge Viper. It offered 505 horsepower and 525 pound-feet of torque—with a six speed manual transmission to boot. A simple engine swap might have made sense, only it turns out classic Dodge trucks from the 1960s aren’t really built for that kind of power. “Switching just the powertrain of the SRT in the old pickup would have been easier, but the old axles and frame couldn’t take 500 horsepower,” says Johann.

After a chat with the relevant authorities (Germany is quite strict with its inspections), a new plan was born. Rather than swap the SRT10 engine into the old D100, he would swap the D100 body on to the chassis of the SRT10. This would provide all the conveniences of the modern truck like heating and air conditioning, and maintain features like the airbags and OBD II port which would be necessary to get the truck road registered in Germany.

“Before starting the swap, I went to discuss everything with the head engineer of the state technical inspection authority (TÜV),” says Johann. This proved crucial to keeping the project road legal. “They outlined that the swap would still be registered as a 2006 Dodge SRT10 and to be fully legal; all applicable safety equipment and OBDII systems needed to stay intact,” he explains. “It meant all emission control systems including catalytic converters and mufflers needed to be stock, with all sensors working.” Even the interior had to remain largely stock. “The original seat and seat belt mounting position needed to be used,” he says. “That’s why we transferred the whole interior to the D100 cab.”

It was going to be a big job, but Johann was more than qualified to get it done. “I did run an automotive repair shop that specialized in American cars and trucks, and I have a long connection to drag racing in different classes for over 40 years,” he explains. “I’m 60 years old now and a certified master technician and welder, and I’m the crew chief of one of three German Pro Mod Teams.” It’s just the sort of resume you’d expect for someone undertaking this sort of work.

“As my work ethic and standard is very high, it was a challenge to make the swap as much as factory looking as possible,” Johann explains. “The connection between the new and old body was carefully trimmed, I don’t know how many times we had to try the D100 cab on the SRT body.”

It was by no means a one-and-done job, with lots of fabrication required to mate the two successfully. “The inner structure of the Door pillars needed to be strengthened, because the doors had no structural support any more,” he says. “We constructed a series of 11-gauge steel plates to carry the weight of the doors and carefully crafted them to the A-pillar support.”

Even seemingly minor parts were given lots of attention. “To keep the HVAC systems and the windshield wiper motor of the SRT10, we redesigned the whole cowl panel,” says Johann. “A new water box with evacuation system was integrated to the section between windshield and engine compartment and spot welded in place.”

Overall, the attitude was not to get the job done quickly, but to get the job done right. “There are absolutely no scrappy or rigged together welds,” he says with pride. “Spot welding, TIG, and MIG welding were used throughout, as needed—no shortcuts taken.”

Regular visits from the relevant officials ensured any bureaucratic hurdles were kept to a minimum. “With the process proceeding, I always invited the TÜV officials to inspect the workmanship, they took pics to document the legality of everything,” Johann recalls. “If I remember, they were in house five times.”

Finally, after five months, the car was ready for its final tests. “The car was inspected at the TÜV Headquarters like a real street car,” he explains. “Emissions testing, brake testing on a chassis brake dyno, road worthiness and so on, including weighing and scaling for its new dimensions.” The truck passed, though the whole process of getting it approved didn’t come cheap. Johann estimates the total bill cameout to around €4,500 to €5,000 (~$4,700 to $5,200 USD).

A swap like this one is far from easy. Even today’s slapdash YouTube swaps take a great deal of work. However, pulling it off in Germany of all places is simply on another level. Government regulations won’t let you get away with dodgy engine swaps and slapped-together builds. At least, not without the Bundespolizei hauling you off the road in short order.

Johann’s skill wasn’t just in getting this swap done, but doing so while playing by all the rules. Those of us living in more restrictive lands could learn a lot from his shining example. Consultation and proper fabrication are what gets you over the line in situations like these. At the end of it all, you’re often left with a better build for your efforts, to boot.

This Dodge D100 now rockets around with V10 power, and looks great doing it—all while in full compliance with Germany’s road laws. That’s a win in our book, any day of the week.

Image credits: Johann Rauch