Max’d Out – Chris Karges’ Classic 1957 Chevy “Hellair” gets Contemporary Duramax Power
Why would Chris Karges put a 6.6-litre GM Duramax diesel engine in a ’57 Chevy? First, 634 reasons, as in horsepower. Second, 1,100 more, as in pound-feet of torque.
In a world of old-school V8s and LS transplants, why not stand out with the choice of power plants? After all, the two-door sedan spent much of its earlier life on a drag strip. Chris found the relic of a race car in upstate New York several years ago at a reasonable price, given its condition.
As Tucson-based Chris says, there wasn’t a wall that his car hadn’t hit. That meant a load of new sheet metal. Chris says every piece of original steel was replaced, except for the floor pan, cowl, roof skin and internal structure pieces. Chris turned to the crew at American Legends Hot Rods and Muscle Cars in Phoenix to orchestrate the extensive build that resulted in the “Hellair.”
First up, the correct underpinnings. All that power – and weight – needs a strong foundation, so a Roadster Shop REVO frame was employed, with rack-and-pinion steering, coil-over front suspension, and a four-link coil-over rear suspension connecting to a Ford 9-inch rearend with 3.00 gears. Wilwood discs, front and rear, are surrounded by Schott Fuel wheels (19×9 in the front, 20×12 in the rear) that are wrapped in Toyo rubber. American Legends’ Tony Arme at said spring weights had to be adjusted because the powertrain combination added about 1,000 pounds to the Chevy.
Most of the external sheet metal was replaced before the vintage Bel Air body could be attached to the modern chassis. In addition, most trim pieces were removed – emblems, door handles, most side trim – and the hood and trunk were smoothed. Other touches included exiting the exhaust through the stock backup-light openings, using a station wagon bumper to house the license plate, and deleting the door vent windows. The engine compartment sheet metal was also heavily tweaked to accommodate the Duramax. The finishing touch was Cadillac Black Diamond paint expertly applied by Hogie Shine’s of Phoenix.
The 6.6-liter Duramax Diesel came from Hausmann’s Diesel Performance in Laurens, New York. The 634 horsepower and 1,100 foot pounds of torque are generated with the help of a Pacific Performance Engineering induction system, valve covers, and headers that connect to stock GM heads. Fleece Performance Engineering components manage the exhaust gases, while the ZF six-speed manual transmission utilizes a dual-disc South Bend Clutch.
Squeezing the Duramax and ZF transmission into the ’57 challenged the American Legends crew, but careful engineering ensured that the engine fit properly beneath the flat hood without hanging below the transmission. The ZF transmission’s dimensions are so different from the vintage transmission that substantial alteration of the transmission tunnel was required, which affected console design and other considerations. The extra effort required by the American Legends team to fit the unusual engine is part of what led ‘Hellair’ to be selected as a finalist for the Chevrolet Performance GM Iron Builder of the Year running, in addition to being our Fuel Curve Pick at the 34th West Coast Nationals in Pleasanton this summer.
The Chevy’s cabin received many custom elements, as well, including 3D-printed door panels, a custom console, and a shaved dash fitted with Dakota Digital instruments and a Vintage Air system. Stitched Envy of Phoenix sewed and fitted the bold red leather upholstery found throughout the interior.
Chris is much younger than his ’57, but he has been around cars for a long time. He says one of his earliest memories is going to car shows in his mom’s ’66 Olds Cutlass. He’s built everything from lowriders to late-model performance cars, but his next project is definitely old school.
“My wife Meg and I love the ‘Hellair’ and soon will build her a 1962 Corvette,” Chris says. “We can’t wait to see how that one turns out.”
Photos by Marc Gewertz & Steven Bunker