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  • This 1956 Duramax DeSoto is built for speed

This 1956 Duramax DeSoto is built for speed

From Early Hemi to 400hp Duramax Diesel Power

Jason Sands
Feb 24, 2016
Photographers: Jason Sands
The recipe was simple: Take one part old car and combine it with another part 6.6L Duramax diesel engine, then go land-speed record racing with the finished product. Little did owner Leon Ekery know at the start of this endeavor that his simple idea would wind up taking four long years to execute.
“I bought an ’03 Chevrolet Silverado 2500HD with the idea of building a Duramax-powered car,” Leon says. As the owner of a salvage yard, Leon has plenty of connections to vintage iron, so when a ’56 DeSoto Fireflite came up for grabs, he knew it was a perfect match for the diesel engine.
Photo 2/21   |   016 DSLP 160600 GM Desotomaxx Grille
With two halves of the grand scheme already in his possession, Leon went about turning the basket case DeSoto into a diesel-powered speeding bullet. While the original idea was to simply swap everything into the DeSoto chassis and call it done, that plan was quickly scrapped once Leon took a good look at the 60-year-old car’s deteriorated front suspension. As Plan B, the truck’s entire front subframe was retained, and a completely new, round-tube back half of the chassis was created to support the DeSoto body.
The suspension is equally trick. In the rear is a four-link setup that uses heavy-duty Hyperco springs and QA1 shocks. The front also needed to be much lower than stock, so Leon sourced drop spindles from McGaughy’s Suspension Parts that, along with torsion keys, bring the nose down by 2 to 3 inches.
Photo 3/21   |   019 DSLP 160600 GM Desotomaxx Front
Perhaps the most radical piece on the car is the rearend. For land-speed racing, a very tall final gear ratio is needed for achieving 150- to 200-mph speeds. Since the correct ring-and-pinion set wasn't available for the factory AAM 1150 rearend housing, Leon was able to convince Currie Enterprises to build a custom 9-inch centersection for the 1150, completing it with a Moser Engineering Wavetrac differential and 35-spline axles, and 2.47 gears from Yukon Gear & Axle.
The DeSoto’s mostly stock, 203,000-mile Duramax does have a hot tune from Adrenaline Truck Performance. The four-wheel-drive Allison 1000 five-speed automatic transmission is also stock internally and has been fitted with a Gear Vendors overdrive unit. The transmission/overdrive package gives the DeSoto enough gearing to reach 250 mph! With its mild powerplant, the DeSotoMaxx hit 141 mph on a 1.3-mile dirt course in El Mirage, California. The team also plans to head to the Bonneville Salt Flats with a 64mm turbo, water injection, and a built transmission, hoping to break the 200-mph mark. In the wild world of land-speed racing, Leon's diesel-powered DeSoto is definitely one of the wildest cars out there—and we look forward to hearing more about its progress.
Photo 4/21   |   021 DSLP 160600 GM Desotomaxx Rear Three Quarter
Fast Facts:
Year/Make/Model: ’56 DeSoto Fireflite
Owner: Leon Ekery
Hometown: El Paso, Texas
Engine: 6.6L Duramax V-8
Fuel: EFILive with tuning by Idaho Rob at Adrenaline Truck Performance
Air: K&N filter on a custom intake
Exhaust: MBRP 4-inch downpipe into a 5-inch flapper stack
Transmission: Allison 1000 five-speed automatic with Gear Vendors overdrive
Horsepower: 400 hp (est.)
Torque: 900 lb-ft (est.)
Tires: 29.0/7.0-17 Dunlop Racing
Wheels: Factory GM steel
Suspension: McGaughy’s Suspension Parts drop spindles and torsion keys (front); custom four-link with QA1 double adjustable shocks and Hyperco springs (rear)
Axle: AAM 1150/Currie Enterprises 9-inch hybrid axle with Yukon Gear & Axle 2.47 gears, Moser Wavetrac positraction unit, and 35-spline axles
Fun Fact: Leon installed a trailer hitch on the DeSotoMaxx “just in case” they want to go after the existing 141.998-mph trailer-towing record Diesel Power set in 2012.
Photo 5/21   |   002 DSLP 160600 GM Desotomaxx Duramax Engine
A ’56 DeSoto is one of few vehicles that has an engine bay large enough for a diesel swap with room to spare. With a smoothed firewall by Shaun Petta at Function Fab, the Adrenaline Truck Performance–tuned (400 hp, 900 lb-ft), 6.6L Duramax engine fits with ease.
Photo 6/21   |   003 DSLP 160600 GM Desotomaxx Computer
Leon Ekery's son, Warren, completed all the wiring, which involved integrating the ’03 Chevrolet Silverado 2500HD’s wiring harness with the project’s transmission and chassis arrangement.
Photo 7/21   |   004 DSLP 160600 GM Desotomaxx Intercooler And Radiator
The expansive front end of the DeSoto is also large enough to incorporate the Chevy pickup’s factory intercooler and radiator. The engine-driven fan was replaced with twin electric units from a Ford Windstar.
Photo 8/21   |   005 DSLP 160600 GM Desotomaxx Downpipe
A free-flowing, 4-inch downpipe and exhaust expel the hot rod engine’s spent gases.
Photo 9/21   |   006 DSLP 160600 GM Desotomaxx Exhaust
The rear window must be Lexan per SCTA rules, which creates a convenient place for the exhaust’s 5-inch flapper valve to exit the car.
Photo 10/21   |   007 DSLP 160600 GM Desotomaxx Rat Cowl Hood
With an engine as tall as a Duramax is, hood clearance can be an issue. Cowl hoods for ’56 DeSotos aren’t top-selling items on eBay, so Leon’s team whipped up a custom piece that clears the turbocharged diesel.
Photo 11/21   |   008 DSLP 160600 GM Desotomaxx Cage
Since Leon and his son are ultimately shooting for a 200-mph top speed, a lot of safety equipment, like this funny car-style rollcage, is needed.
Photo 12/21   |   009 DSLP 160600 GM Desotomaxx Door And Window
Leon and Warren incorporated vintage touches into the build wherever possible. Even with Lexan windows and an aluminum door panel, the door handle and window crank are original DeSoto pieces.
Photo 13/21   |   010 DSLP 160600 GM Desotomaxx Rear Back Half
All you need is one look at the rear of the car to understand why completing the project took as long as it did. The all-tubular back half reminds us of a NASCAR stock car and is home to a custom, hybrid 9-inch rearend with 2.47 gears, a 1,000-pound weight plate, 25-gallon fuel cell, and advanced fire-suppression system. The rear suspension is a four-link design that incorporates QA1 shocks and Hyperco coilover springs.
Photo 14/21   |   011 DSLP 160600 GM Desotomaxx Batteries
With traction at places like the dry lake beds of El Mirage (California) and Bonneville Salt Flats in Utah being critically important, heavy items such as twin batteries are positioned at the back of the DeSoto. This gives the car an interesting 46 percent (front), 54 percent (rear) weight bias, which is the opposite of most diesels.
Photo 15/21   |   012 DSLP 160600 GM Desotomaxx Wheels And Tires
Four 7-inch-wide, 29-inch-tall Dunlop racing tires from Cowboy Tire Service are some of the only tires that can handle the car's weight and speed. They’re mounted on factory GM dualie wheels and tuck neatly inside the DeSoto body.
Photo 16/21   |   013 DSLP 160600 GM Desotomaxx Parachute
Stopping a 7,100-pound, diesel-powered missile is a genuine concern, so only the best safety equipment—like this large DJ Safety parachute—is installed on the DeSotoMaxx.
Photo 17/21   |   014 DSLP 160600 GM Desotomaxx Power
An outside electrical shutoff switch (for both the battery and the alternator) is another safety item. The switch can shut the engine off in situations when the driver is incapacitated.
Photo 18/21   |   015 DSLP 160600 GM Desotomaxx Fire
Perhaps the DeSoto’s most advanced safety feature is the Emergency Suppression Systems fire system, which is plumbed throughout the entire car and uses twin bottles for a massive volume.

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