Robert pursues an ambitious electric conversion on his BEAST of a K10 truck. Along the way, he test-drives two fully-electric cars: the Army's latest tactical vehicle and the world's fastest-accelerating production car.

As a child, Robert's true love of driving came from his mom, a real daredevil on the road. She left him her old Benz, and he treasures it to this day. Now he's restoring it with the help of his son, Exton, and a crack crew of diesel experts.

Robert LOVES the design of his '66 Buick Riviera -- but it's one of the most fuel-inefficient cars ever made. In the 1960s, it was sold as "the car of the future." Robert plans to perfect the Riv by updating it with a stunning, one-of-a-kind rebuild.

How do you improve upon a pristine all-original '65 Corvette? Well, if you're Robert Downey Jr., you convert it to an EV! Purists won't be happy, but Robert has something to prove, and he's taking his electric Vette to the drag strip to make his point.

Robert has an all-original, low-mile '85 El Camino. But as he often says, "She's perfect, so I have to start over." He's out to turn it into a meaner and greener off-roading champ. When it's done, he takes his wife Susan on a hair-raising maiden voyage.