Inside DC MotorWerks: A 300 SL Gullwing, a 103,000-Mile Murciélago, and the Manual Row

The first time Cameron Davis came on Throttlecast, he told the story of DC MotorWerks from a studio chair. For his second appearance, Grant Brewer and Dave Codrea went to the shop in Alpharetta that Cameron runs with his partner Andy. It was a working day, so the lifts were full and the fabricator kept welding while the camera rolled.

If you haven’t heard Cameron’s first episode, it covers how he started the business in 2020 and how the manual swaps began. This one is the tour.

The lobby and the R129s

The lobby is a car guy’s den, with memorabilia from their friend Ed Bolian of VinWiki. Bruno, the shop dog, is the mascot.

Out back, the first cars you see are R129 SLs. That generation was Cameron’s first car and is the reason he got into Mercedes, and there are usually five to ten of them in the building. The shop owns two or three of them. The name DC MotorWerks goes back to the same period. DC stands for DaimlerChrysler, the era when Cameron and Andy got deep into the brand. Andy started working on them in 2005.

A V8 where a V6 used to be

One of Cameron’s favorite cars is the W211 E-Class, and a 2009 E350, the final model year, was getting a 5.5-liter M273 V8 in place of its V6. Nothing was wrong with the original engine. The swap was purely the owner’s choice. He had already added a lip spoiler, a carbon trunk lid, wheels, brakes, and interior pieces to make it look more like an E63.

The swap is less dramatic than it sounds. The V8 is the same modular engine design with two extra cylinders, so it bolts in with factory parts. The work is in the ancillaries: the radiator, hoses, and AC lines, then a lot of software coding to make the car happy with eight cylinders. The shop uses a donor engine with similar or fewer miles than the car. The owner gains about 100 to 110 horsepower, and Cameron suspects a manual swap is next.

A 1955 300 SL Gullwing in pieces

In the back sat a 1955 Mercedes 300 SL Gullwing belonging to Tyler Hoover of Hoovie’s Garage. The 70-year-old engine had given out on a drive, and it was at the machine shop for fresh bearings and a full rebuild. Parts haven’t been hard to find, Cameron says, thanks to reproduction specialists in Europe.

The car is a lesson in 1950s engineering:

• The transmission comes out through the interior, over moving blankets laid on the sill.
• The steering wheel folds down with a small chrome latch, a racing feature for quick driver changes.
• It has a tube-frame chassis and a dry-sump oil system.
• The washer reservoir looks like a square mason jar, and the brake fluid reservoir looks like a small paint can.

Cameron also points out that these were among the first gasoline cars with direct injection, a technology that is everywhere today.

The Murciélago that gets driven

DC MotorWerks rarely goes without an exotic. At the time of the visit, it had a 2003 Lamborghini Murciélago with a factory gated manual and 103,000 miles. The engine had started consuming coolant, so the V12 was out of the car with the heads back on, waiting on valve shims. Cameron walked through the engine’s history. The Bizzarrini-designed V12 dates to the 1960s and ran through the LP640, growing from about 3.5 liters to 6.5 liters on the same basic design.

The owner has had the car about 14 years and put more than 60,000 miles on it. He has changed its color four or five times. It started in pearl yellow, went to bright Verde Ithaca green, then a red chrome wrap, and has been painted white twice. He went to the dealer to buy a Gallardo, and the salesman talked him into the Murciélago instead. When the front differential locked up on the way down a mountain into Las Vegas, he rocked the car until the input shaft snapped, drove it down, and had a local shop convert it to rear-wheel drive. It’s still rear-wheel drive, and he has enjoyed every mile since.

Manual swaps on cars that never had a shifter

Two projects on the lifts push the manual-swap program further.

• CL63: the first car of that later big-coupe generation to get a manual. It has an electronic shifter from the factory, so there was never a hole in the tunnel for a gear lever. The shop is fabricating one and building a center console that will be finished in wood to match the factory trim. The same owner has a CL65 he wants converted next.
• E63 wagon: Cameron calls it the highest-MSRP E63 in existence, a full designo build with white wheels and badging, ceramic brakes, and saddle leather on nearly every surface, down to the rearview mirror. A friend who worked in designo at Mercedes saw it and said he built that car. It’s in line to be the shop’s first biturbo car to get a manual.

What OEM plus means

The finished CLK63 Black Series shows the idea best. It’s a factory widebody track car from the 2007 to 2008 era, a pillarless coupe on what is essentially a C-Class chassis. Cameron says it was the car that most needed three pedals. “It just gives you the feel like this was proper.”

About 90% of every swap is factory Mercedes parts, down to the shift knob. “Deep down, Andy and I aren’t super modification guys,” Cameron says. “We like things proper and factory.” The 10% they make or change is mostly the clutch, the panels that delete the shift paddles and buttons, and sometimes the transmission crossmember.

That matters because most customers are out of state. Only two or three of the swaps have stayed in Georgia. With factory driveshafts, flex discs, and engine parts, an owner can take the car to their own Mercedes dealer for service. “You’re really just using their stuff to make something they didn’t.”

The manual row and the collection

The finished cars lined up outside tell the rest of the story:

• A C63 coupe built to look like a Black Series, with a full mechanical restoration, new cams and tappets, and suspension work.
• The shop’s first R129 manual, a V12 SL. No Mercedes bell housing matches, so it uses a European adapter with a Getrag gearbox. It’s headed to South Florida for paint.
• A C63 headed to Oklahoma in the same color scheme as the car in the Top Gear test against the RS4 and M3, with a resonator delete.

Then the shop’s own cars. A 1997 SL La Costa edition is one of 30 made for a PGA event at La Costa. Two were media cars and 28 were sold. It’s Calypso Green with a matching two-tone interior and the club’s logo on the shifter. Cameron believes only the SL Formula One edition is rarer among R129s. Next to it was a 2002 SL in triple silver with the SL2 package, which includes sport package, xenon lights, and heated seats.

The last one hurt. Cameron and Andy bought a one-family 2008 E63 wagon with 37,000 miles on Bring a Trailer and paid the most they ever have for a car. Cameron says only around 150 came to the US. It’s in line for a manual swap as a shop project, and then it will be sold. Andy, who owns 124, 210, and 212 E-Class wagons, may decide he needs the 211 to complete the set.

Watch the full episode

The full shop tour with Cameron Davis is above and on YouTube, including a walkaround of the Murciélago V12 on the floor. Book service or a manual swap through DC MotorWerks.

Cars like the E63 wagon and the La Costa SL need the right place to sit between drives. The Ride Lounge offers climate-controlled car storage in Atlanta, with monitored bays in Peachtree Corners and Midtown and a floor where these stories get told. For a private event among cars like these, look at venue rental.