Mercedes-Benz V12-swapped AC Cobra replica

The only thing this Cobra lacks is weight

Photographers: Anders Odeholm, The Media Factory AB

THIS insane AC Cobra replica hails from Sweden but would look at home turning stunts in a Hollywood action flick like Fast & Furious. Just as Carroll Shelby took a little English sports car and gave it an American heart to create the legendary Shelby Cobra, Magnus Jinstrand moved the concept to the next level, melding a replica Cobra body with a supercharged Euro mill.

This article was first published in the May 2011 issue of Street Machine

Magnus’s automotive tastes follow a weird Euro-American trend. He got into American cars by reading magazines as a kid and riding in his cousin’s ’65 ’Stang. His daily driver is a GMC Sierra Denali on 22-inch rims and he’s owned European sports cars, including a Porsche Turbo and an M3. But he says he was attracted to the Cobra, DeTomaso Pantera and Ford GT40 due to their sports car designs, with relatively uncomplicated technology and American engines.

And yes, this Cobra shares the shed with an off-its-face 600hp Pantera and a Ford GT40 replica, both painted in a similar grey to the Cobra.

“I showed the Pantera at the 2008 Custom Performance Show in Jönköping, Sweden,” says Magnus. “There was a 427 Cobra kit car next to my Pantera and it struck me that I should build one. I’d been thinking about it for years but kept putting the idea aside because of other projects. I placed an order for a DAX Cobra body and frame at the show. That really felt good!”

Mercedes-Benz V12 Cobra rear

Rondell 18 & 19in wheels over Brembo brakes fill the swoopy ’guards of the DAX fibreglass body. The whole package weighs in around 1000kg

Not half as good as it must feel to feed the gas into the blown Mercedes-Benz V12 shoehorned into the front of the Cobra. That’s right, instead of his beloved American muscle, Magnus found European units more readily available and he planned to use a Mercedes V8 for something different. But the junkyard supplier had this V12 from an S600 sedan and, you know, why not?

These engines make an effortless 400hp in stock trim but it was gonna have to do better than that to keep up with his Ford V8-powered Pantera and GT40. So a suitably Swedish Lysholm 3300 supercharger pumping around 0.7bar of boost through a custom intake manifold and intercooler helps the Teutonic V12 punch out closer to 600 stallions.

Even though it was never going to fit under the Cobra’s low bonnet, Magnus wanted the supercharger as low as possible so a lot of effort went into making the manifold squat down in the V of the engine.

“I didn’t want it to look like a Pro Streeter, so we worked hard to make the blower manifold plate as low as possible.”

A plenum was fabricated from 10mm aluminium plate to sit between the blower and the engine and take the force-fed intake charge from the huffer to the front-mounted intercooler and back to the factory Mercedes-Benz intake manifolds. The engine remains internally stock yet it took Magnus and his mates five months to set it up. Most of the work was done in his fully equipped home garage and included fabricating the drive pulleys and belts for the front of the engine, the pipes to and from the intercooler and the twist of exhaust headers.

With Mantrop Park Raceway just 20 minutes from home, he likes to get out for track days so the Cobra was always going to have a track-car theme but the idea of the wild wings came when a mate parked his Carrera Cup Porsche in the garage.

“Looking at the huge rear wing on the Porsche, it struck me that it would actually fit on the Cobra and look great. Then I looked at the front end and realised that a modern front spoiler with splitter would also look good on the car.”

Magnus made a copy of the Porsche’s wing and fitted it to the Cobra using custom mounts that go through the body to the rollcage. The front spoiler was another job altogether. Inspired by a photo of a 70s Camaro race car, Magnus formed a spoiler from wall cavity spray-foam insulation then worked it into the desired shape before making the final piece in carbon fibre.

Compressed air is fed to the intercooler at the front then back to the V12 Benz donk. The snakepits of custom pipework either side of the engine send spent gases to the side pipes

“I hoped the design would prevent air getting under the car and creating lift. I’ve done a few high-speed passes and it seems to do the job. We spent countless hours on it and I couldn’t be happier with the result.”

The 427 Cobra is a menacing looking car on the track or street but the oversized front and rear spoilers, protruding supercharger and flat paint give Magnus’s interpretation of the classic a truly sinister look.

Getting the Cobra on the road hasn’t been without problems. The engine wouldn’t rev above 5000rpm; after much fault-finding that was fixed by remapping the ECU. Then, when Magnus put his foot down, the supposedly unbreakable Corvette axles turned pretzel-like and had to be replaced with custom chrome-moly versions. There was also an overheating problem but Magnus says that’s been sorted.

“I tested the car against my Pantera and the Pantera lost! The DeTomaso covers the quarter mile in 11.5 seconds and sprints from 0-100km/h in 3.3 so it seems that the Cobra is pretty fast. I’ve driven quite a few fun cars in my day and the Cobra is in a league of its own.”

Lightweight Tillet racing seats with harnesses and Auto Meter gauges in a carbon fibre dash carry the race car look through the clean and simple cockpit

That’s not surprising considering Magnus has 600 ponies hauling a 1000kg track-inspired roadster. Now all he has to do is wait for the winter snow to melt so he can get into some real testing on the track. Then he wants to rebuild the GT40 so it can keep up with the Cobra and Pantera. And there’s a ’68 Charger lurking in the back of the garage waiting for a similar extreme-Euro makeover.


Colour: Flat grey

Engine: Mercedes-Benz V12 6.0l
Intake: Custom manifold, Lysholm 3300 supercharger, twin Volvo 960 throttlebodies with K&N filters, KL Racing intercooler
Fuel: Dual Bosch fuel pumps, 50-litre tank, 98-octane unleaded
Exhaust: Owner-made 15/8in stainless headers, 4in side pipes
Cooling: Custom 670x370mm copper radiator

’Box: Getrag six-speed manual
Clutch: Sachs
Diff: C4 Corvette, custom axles

Chassis: DAX 40x80mm tube
Front suspension: C4 Corvette with GAS coil overs and Öhlins springs. Adjustable sway bar
Rear suspension: Chrome-moly four-link, GAS coil-overs, Ohlins springs, adjustable sway bar
Steering: DAX rack and pinion, Ford Sierra column
Brakes: Brembo 330mm discs & four-piston calipers (f), 290mm & two-piston (r)

Rims: Rondell aluminium, 9½x18 (f), 11×19 (r)
Rubber: Pirelli PZero Corsa, 245/35-18 (f), 295/30-19 (r)

Leffan, Mattsson, Emil, Pelle, Agge, Davve, Jevlar, Fredde, Micke Wunderbaum, Rejmes Skadeservice, Vikingstads Svetsteknik, Linköpings Bil & Marin Textil, Linköpings Stål, Swea Kardan, Wurth and all the others who helped me in one way or another. A special thank you to Pirelli Sweden and most of all a big hug to my wonderful wife Linda for putting up with all my Cobra craziness