At this year’s Pebble Beach Concours d’Elegance, the Southern California performance-car manufacturer Saleen unveiled its first all-electric model, the Saleen Foursixteen. Known for building versions of U.S. muscle cars, such as the Ford Mustang and the Chevrolet Camaro, from the chassis up, as well as its own supercar, the S7, Saleen has marked out an intriguing new direction with the introduction of an electric vehicle.

A radically restyled version of the Tesla Model S P85, the Foursixteen (starting from …