Perhaps because their Darth Vader appearance and epic performance came with the unlikeliest of badges, we have always had a soft spot for the Buick Regal GNX. But that isn’t what you’re looking at.
According to the folks at Diesel Power, what you’re actually drooling over is a GM Duramax diesel-powered 1981 Oldsmobile. Sort of. As the story goes, owner David Morad loved his Duramax-equipped truck, but he wanted to swap the monstrous 6.6-liter turbodiesel into something lighter. Enter the Buick Regal.
Morad located and purchased a 1982 Buick Regal diesel, only to have it self-immolate on the drive home thanks to a gasoline leak—at some point, a previous owner had dropped-in a gas engine). Undeterred, Morad located a 1981 Oldsmobile diesel (presumably a Cutlass), and then turned it into GNX piece-by-piece. This apparently entailed cutting the car in half, welding on the rear clip from a Regal, and raising the floorpan to accommodate the new engine’s exhaust system. A new front-strut subframe, custom aluminum fuel tank, rack-and-pinion steering unit, and a set of Wilwoods were also part of the plan.

As of the article’s writing, Morad’s nearly 4500-pound GNX clone runs an 8.25-second eighth mile (around a high 12-second quarter mile) and returns 28 miles-per-gallon. Much more remains on tap with some better tuning and more traction.
Click on the link for Diesel Power’s full blow-by-blow build-up and a gallery of this incredible Buick Oldsmobile. + Diesel Power: 1982 Buick Regal - Darth Vader: Diesel Alternatives