BOLDER BENZ: A 450 SL BECOMES A 140-MPH SUPERCAR
True To Its Roots
With double the power of a stock Mercedes-Benz 380SL R107, and restyled using factory pieces, the R 107-based #DMS
4.7 is a glimpse into the ’80s that could have been. Words And Photography By Jeff Koch / Illustrations Courtesy #Neil-DeAtley
Original concept illustrations showing the front, rear and side of the proposed DMS 4.7. The stunning finished product strays little from the illustrations, down to the color and wheel style.
Neil DeAtley had issues with the Mercedes-Benz-380SL-R107. Considering Mercedes’ great motorsport history, much of it achieved with cars called SL — the race-winning and technologically advanced 300 SL gullwing, the W198 roadster models, the delightfully chuckable W113 series — the 380SL R107 of the early 1980s stood firmly at odds with that history. With just 155 emissions- strangled horses under the hood, and pushing two tons at the curb, the SL managed to be neither Sport nor Leicht (Light) as its name suggested.
Neil himself was working on making some of his own history with the machine dubbed by wags as the panzerwagen. Racing historians among our readers may recall that DeAtley Motorsports won the 1983 SCCA Trans-Am championship in a pair of Camaros driven by David Hobbs and a young Willy T. Ribbs. What fewer will recall is that, for two arduous seasons before championship glory showered laurels and champagne and sweetmeats upon him, Neil ran a single-car Trans-Am effort using the R107 Mercedes SL as his steed, the number 45 on its doors and the late Loren St. Lawrence as his driver. It was an entirely independent effort, with no factory backing for what was then a not terribly high-visibility series.
The ’1981 and ’1982 seasons were rough going for DeAtley Motorsports, and there wasn’t much glory in it. The team’s best start was second at Road America, though they only completed eight laps. Its best finish in 1981 was at Trois Rivieres, starting 15th and finishing in 8th, taking home a cool $1,000 in prize money. The ’1982 season was stronger, perhaps thanks in part to an influx of sponsorship cash (see sidebar), finishing half of the eight races under its own power: as high as 7th at Sears Point and a career-best 6th at Road America. If nothing else, the DeAtley Motorsports crew back at the Salem, Oregon, works had learned what it took to make an R107 perform at or near the front of a pack of much newer cars that were, in the main, lighter and better suited for on-track derring-do.
But there was another issue at play. Neil owned Columbia Motors of Kennewick, Washington, in the early 1980s, one of the Pacific Northwest’s larger Mercedes dealers. He had a vested interest in moving metal; anything that prevented him from doing that was a concern. The 380 SL’s sitting in his showroom did not reflect even a whiff of his race team’s efforts. While hot five-liter versions of the SL stayed home in Europe (and occasionally strayed stateside, thanks to gray-market importation loopholes), the light-duty 380 SL became the unofficial cars of Ladies Who Lunch in America’s swankier metropolitan power centers.
Also, by the mid-’80s, the R 107’s early ’70s style looked positively fossilized. Today, we can natter on about the SL’s style, throwing terms like classic and enduring, but they’re just euphemisms. The R 107’s shape had not significantly changed, beyond bumpers, since its early ’70s introduction; aerodynamic efficiency was an ’80s buzzword, and the SL was designed in an era when such things were not taken into consideration. Many wondered why Mercedes was taking so damned long to update its hearty perennial, the SL. Neil DeAtley was one of those people.
Unlike the contemplative many who stroked their chins and pooh-poohed the reality before them, Neil did something about it. That something is the machine you see here: the DMS 4.7. A fully functional prototype for a low-production SL meant to be sold through his dealership and beyond, the DMS 4.7 was a clean update, using Stuttgart parts; it made you wonder why Mercedes couldn’t execute its own facelift with such aplomb.
Neil started with a 1975 450SL off his dealership lot. The blunt face of the R 107 was smoothed back to something far more in keeping with the style of early ’80s Mercedes. Out went the four round sealed-beam lamps and bumper jutting out nearly a foot in front of the body; in came a more aero-friendly vision, utilizing a contemporary Mercedes SEC grille and headlamp/turn signal units. The hood and front fenders were based on Mercedes originals, but had extensions that were seamlessly hand-formed in steel. New fiberglass front and rear bumper covers were carried down the side of the car visually with new rocker panels. Trim was largely either blackened or painted body color (grille and wheels aside), in keeping with the then-fashionable ’80s monochrome vibe. Slather it in hooker-lipstick red, and you can’t help but look.
With looks like that, there had better be the guts to back it up, and luckily there were. The four-and-a-half liter iron-block V-8 was bored out to 4.7 liters, and was given the usual array of hot rodding tricks: a port-and-polish job on the factory aluminum cylinder heads, forged Arias pistons that (in combination with the worked heads) bumped compression to 10.5:1, a set of high-lift cams, and tubular headers. These items alone were said to nearly double the power of a stock 380SL — 297 horsepower. Away went the mandatory automatic transmission, and in came a slick-shifting Getrag five-speed. Noted racing photographer Pete Lyons saw 138 MPH behind the wheel, and (in his Car and Driver story) claimed there was more left when he had to back out of it. Put up against a contemporary 380 SL, with its terminal velocity of 115 MPH, the promise of 140 sounded pretty good.
The suspension was sharpened up as well. Bilstein gas shocks and adjustable anti-roll bars front and rear joined with higher-rate coils (420 pounders in front, 320 pounders in back) to help lower the ride height three-quarters of an inch and to prevent acceleration squat, brake dive and rolling in the turns. The rear suspension arms were altered at their pickup points, so that camber change would be minimized. Brakes were fourwheel Lockheed discs: 13 inches in front, 11 inches in the rear, although production models would have used standard calipers and more aggressive brake pads. Sixteen-inch V-rated Goodyear Eagle tires (sized 225/245) were fitted to Centra wheels, seven inches in front and eight inches wide in back.
The cockpit was also massaged to contemporary standards: power Recaro buckets, leather-trimmed to match the rest of the interior; new door panels featuring accents made of Zebrano wood; Wilton wool carpeting; the finest Alpine stereo system the mid-’80s had available; a leather boot for the five-speed’s closethrow shifter. What price exclusivity?
Well, about $75,000 in 1985 dollars, which sounds slightly less mad when a new 380 SL was in the $43,000 range and the engine work alone ran to $15,000. Alas, as is often the case with such flights of fancy, the DMS 4.7 didn’t sell. Two were made, and Neil himself retains this example in his extensive personal collection of Mercedes models (roughly two dozen postwar three-pointed stars light up his garage).
It’s clearly Mercedes, clearly ’80s, and has more than a whiff of AMG about it, even though the famed tuning house had nothing to do with its creation. It still wasn’t light, pushing 3,800 pounds at the curb, but there was no doubt that the Sport part of the SL’s moniker had returned to the equation. A legacy of the DeAtley Motorsports contribution to the Trans-Am wars? Absolutely, although we suspect that the race car was more famous, and got more visibility, than the DMS 4.7. Today, with three decades of hindsight at our disposal, the DMS 4.7 looks like the missing link between the R107 and the 1990 R129 — a high-performance ’80s Mercedes SL that never was. It makes us wonder what might have been.
Weekends were made for… Trans-Am racing?
With its privateer 450SL R107 effort, DeAtley Motorsports ushered in an innovation that didn’t get a lot of credit at the time: bringing big-name sponsorship to a Trans-Am car.
Recall that the factory Trans-Am teams of the ’60s didn’t sticker their cars up like a NASCAR racer, rather using only contingency sponsors and manufacturer graphics. This clean-flanked approach remained through the Trans-Am series’ privateer ’70s. In 1981, DeAtley Motorsports entered SCCA Trans- Am in its privateer Mercedes-Benz 450SL. The late Loren St. Lawrence drove that car for the entirety of the 1981 and ’82 seasons.
But something changed toward the end of 1981: For the last three races of the 1981 season, the formerly white SL was now black, and sported foot-high lettering for Michelob beer across each door, and the hood. The livery remained in 1982.
Now, who can say which came first, but according to St. Lawrence’s obituary (he died in 2014), he was hired as the director of motorsports marketing and sponsorship for Anheuser-Busch in 1982. It cannot be a coincidence that a Michelob beer sponsorship appeared on the side of the DeAtley SL starting in late 1981, and running clear through to the end of the 1982 season. Can it?
There’s no mistaking the cabin for a Mercedes, although it looks a bit more welcoming to the serious driver, thanks to the leather-covered power Recaro chairs and the manual shifter poking up through the console. Real Zebrano wood inlays added an extra touch of class.
The engine looks stock enough, but the usual hot-rod tricks—an overbore, hotter cams, porting and polishing the heads— brought the DMS to within spitting distance of 300 hp.
TECHNICAL DATA / #1975 #Mercedes-Benz-450SL-DMS-4.7-R107
R107 / #Mercedes-Benz-R107
Engine SOHC #V8
, iron block and aluminum cylinder heads
Displacement 4,679 cc (286- cu.in.)
Horsepower 297 @ 5,500 RPM
Compression ratio 10.5:1
0 to 60MPH N/A
Top speed 138+MPH*
Overall length 178.4 inches
Overall width 70.5 inches
Overall height 50.5 inches
Wheelbase 96.9 inches
Curb weight 3,800 lb.
*Source: Car and Driver, February 1985