“How many custom details does this Challenger have? Oh, at least 50. There are pressings in the door sills,
side marker lights, brake lights, door handles, valve covers… Wait. Fifty might not be enough.”
Those are Peter Karlsson’s words, and he has truly taken his 1970 Dodge Challenger to a whole new level – a level where trophies and awards have rained down upon Karlsson and his Mopar® vehicle in recent times. In his home country, the Challenger has been featured in extensive articles in leading Swedish automotive magazines.
Now, it’s time to spotlight this masterpiece beyond national borders – into Europe and the United States.
Because it deserves it.
When I ask Karlsson for a list of all the modifications, there’s a slight pause. I hear him take a deep breath.
Then, he concedes.
“If I were in the garage with the car, maybe. But there are about a hundred modifications. It’s quite a bit,”
Karlsson says with a mild smile.
Yes, we’re talking about valve covers. Center caps for the wheels. Various emblems. A battery box, the word “Mopar” pressed into 2 millimeter sheet metal and welded into the car’s subframe connectors, position lights and brake lights. We’re talking about air filters, door sills, rear axle covers and brackets for the trunk hinges. The intake manifold and door handles … the list goes on, seemingly without end.
Many of the Challenger’s details take time to discover. Some are quite clever – like the aforementioned Mopar pressings under the car or the trims inside the hood’s air intakes, visible only when viewed head-on.
Why these hidden details, Karlsson?
“I want all the modifications to look factory-made, as if they were there when the car left the assembly line. That way, the observer doesn’t notice all the details at once. They blend in with the car,” Karlsson says with a wry tone.
Karlsson works as a model maker and toolmaker, meaning he processes metals using milling machines, creates models with CAD, and fabricates the tools used in pressing and casting. In short, he works with this kind of thing daily and is highly skilled at it. That makes his free time a bit easier – and, above all, much more stylish.
But not necessarily faster.
“It all started when I blew the head gasket on the Challenger during a street race. It took me 19 years to
replace it. Yeah, I made some other modifications, repairs and changes along the way too… If I hadn’t
procrastinated, bought another Challenger and a Dodge A100 van as well, it might have gone faster. In terms of effective time, it probably took about half of those 19 years to complete the car. But I couldn’t put anything back on the car without modifying it. I always thought, ‘I could make that thing better. Or
prettier,'” Karlsson says.
He adds that some people probably don’t realize how long such a build can take. Even though the Challenger was in relatively good condition when Karlsson bought it nearly two decades ago, there was still work to be done. Poor repairs had to be fixed.
“I’ve gone through the entire car. Replaced all the interior. Repaired rust where necessary. But mostly, I
fixed things from when the car was last restored in the 1980s. For example, they filled all the body seams
in the engine bay back then. That’s how it was supposed to look at the time – completely smooth. But I wanted them visible. I also widened the wheel housing by four inches on each side and shortened the rear axle, among other things,” Karlsson says.
This leads to the discussion of the engine and drivetrain. Let’s start at the back and work forward, in line
with how solid performance in a muscle car is built. The Challenger retains its original rear axle, a Dana 60
with a 4.11:1 ratio, which pairs best with the manual 833 gearbox the car originally left the factory with.
Today, the Challenger – a genuine Six Pack car – has a 727 automatic instead. However, the 440 engine is still matching numbers.
“What I’ve done with the V8 is remove the nitrous oxide system and added a bit more displacement. Today, the block is overbored by 0.06 inches and stroked to 502 cubic inches. With the original Six Pack intake, including the three carburetors, the V8 produces 624 horsepower at the dyno and 911 Newton-meters of torque,” Karlsson explains.
The torque, in particular, is impressive. Karlsson mentions that his camshaft is quite mild.
“It has 0.580 inches of lift. Not the sharpest camshaft from Competition CAMS. But I want to be able to drive the car on the street too,” Karlsson says.
He adds that while purists often store the car’s original engine and use a replacement V8, he does the opposite. Karlsson tunes the original engine and drives with it. Things are meant to be used.
So, what does the performance amount to? At one time, the Challenger ran the quarter-mile in 10.8 seconds with nitrous.
“I think it will perform about the same now. But no, I don’t have a roll cage. So when I do test it, I’ll have
to make the most of it the first time. If it runs under 11 seconds, there’ll be no second run,” Karlsson says with a laugh.
Back to the Challenger’s exquisite details. Look at the decorative stripe running along the Dodge’s sides. Do you notice that the corners are slightly rounded so they won’t catch on the sponge when washing the car? Do you see how each stripe becomes two millimeters wider relative to the one behind it, from the car’s forward-moving perspective?
“The inspiration comes from the AAR ’Cuda, but here the stripe is divided into bands all the way through. It’s also a bit taller than the AAR decal, which also has sharp corners. I tested the design with tape for quite a while, probably several days. Then I CAD-designed it and sent it to a decal printer. Yes, it’s kind of a ‘sickness,’ wanting to design everything yourself. At work, I manufacture parts for the Swedish truck brand Scania, and you can’t change their orders even if you’d like to. So it’s nice to make all the decisions for your own projects,” Karlsson says.
He adds that he likes the visual effect the stripe creates in different situations. In sunlight and street lighting, it stands out well, while under other lighting conditions, it becomes more subtle.
Karlsson will turn 60 shortly. During the photo shoot, he says the Challenger is his last major car project. But during the interview a few months later, he is more hesitant about that statement. Karlsson is currently building and restoring a van – a Dodge A100. An advanced project. So, what are his thoughts now?
“Well, maybe it’s not entirely accurate that ‘the Dodge was my last major car build.’ The A100 has loads of wood details, like oak sun visors with orange stitching. The cabin lighting is made from Absolut Vodka bottles, also crafted from wood. It just happens when you’re a furniture maker by trade. In the Challenger, all wood details were replaced with aluminum, but in the A100, I’m going the opposite way – loading it up with wood instead,” Karlsson says.
The A100’s taillights are a story in themselves and perhaps add another piece to the larger van puzzle.
“I needed new reflectors for the taillights, so I cut them out of two polished stainless-steel dog bowls. By chance, I measured the remains of one bowl against one of the taillights, and it fit perfectly – down to the millimeter! So now the van gets those taillight surrounds. People can hardly keep from laughing when I tell them. It was a bit harder to avoid laughing when trying to find new dog bowls of the same size to cut from for a more perfect result. I had to order bowls from three different pet stores before I found the right size again. Yeah, the pet store staff were quite puzzled when I needed the exact internal diameter, and they didn’t find it easy to measure either,” Karlsson says with a smile.
By Christmas 2024, the van will be painted on the inside. After that, assembly and exterior paint await. Karlsson has no high hopes of finishing by summer 2025, but by 2026, the van should be ready and rolling for the first time since 1978. I’ll have to return for a feature then because if the A100 is even half as stylish and tough as the Challenger, Karlsson will have created another award winner.
P.S. If you, for some reason, want to get in touch with Karlsson, he can be reached at challengersixpack@gmail.com. I can’t promise he’ll reply, he’s very busy building a Dodge A100!
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