The delicious details of the Jaguar Roadster conversion

The car is a vintage silver-blue 1968 Jaguar E-Type Roadster with one crucial, and major, modification: Its famous six-cylinder gasoline-powered XK motor was replaced with an all-electric drivetrain.

 The newly married Duke and Duchess of Sussex left Windsor Castle in a Jaguar Roadster that was modified to be all-electric. Steve Parsons/Press Association, via Associated Press

The newly married Duke and Duchess of Sussex left Windsor Castle in a Jaguar Roadster that was modified to be all-electric. Steve Parsons/Press Association, via Associated Press

Where the motor had been, Jaguar Land Rover technicians installed a lithium-ion battery pack capable of powering the car for about 170 miles on a charge (less than Tesla’s new Model 3 mass-market car, but perhaps the Jaguar has better braking). And in place of the gearbox, they installed a 220-kilowatt electric motor.

All of that was done without cutting or otherwise modifying the car’s frame, and the new drivetrain weighs about the same as the old one, so there was no need to change the suspension. Such “nondestructive modification” is important, said Nathan Hoyt, a spokesman for Jaguar Land Rover North America, because while owners of vintage Jaguars may wish to switch to an all-electric drive, they may want to reinstall the gasoline motor to sell the vehicle.

“It gives customers options without having to worry about doing permanent harm to the car,” Mr. Hoyt said.

A few other changes were made: the dashboard was swapped out with a new one with gauges to monitor electrical performance, the vintage incandescent headlights were replaced with more efficient LED bulbs, and the gas tank fill tube was removed in favor of an electrical coupling for charging the battery.

Many viewers noted that the steering wheel was on the left-hand side; Mr. Hoyt said this particular car, a one-off prototype that was first shown last fall, was originally exported to the American market after it was manufactured 50 years ago.

Jaguar Land Rover has been weighing reaction to it and may decide to go ahead with a program in which customers could order a new, all-electric E-Type or have their existing vintage car converted at the factory.

Either way, an electric Jaguar won’t come cheap. Mr. Hoyt said that a complete factory restoration of an E-Type that remains gasoline-powered typically costs about $390,000. An electric version would cost even more.