Jaguar has converted a classic 1964 E-Type to battery-electric:
This is not a production model, or even a prototype... it's just a publicity item to go with their announcement that all of their products will be electric or hybrid by some future date (which is a bit like announcing that the weather will be colder when winter comes

), although Top Gear says the conversion parts are a prototype of what might be offered to convert various classic Jaguar models.
The interesting part is that they apparently didn't want to mess unnecessarily with the original car, so as little as possible is changed and the new powertrain fits neatly in place of the original.
- the battery pack is a single box in the space of the original engine
- the 220 kW motor is in place of the transmission
- the original suspension and final drive (differential) are intact
Cost is no problem for this sort of project, and the original engine is large, so they were able to jam 40 kW-h of battery capacity in that space. DIY conversions typically can't manage this, and battery packs occupy other parts of the car, even with much lower total capacity.
There is no transmission mentioned, and it seem unlikely that there would be room for a multi-speed transmission, but I didn't see any indication of whether or not there is a single-ratio reduction gearbox on the motor output.
There is a claim that some parts from the I-Pace were used, but that could be anything. Neither of the provided specs (battery capacity or motor power) match the I-Pace, which is not yet in production.
The car either weighs 80 kg less or weighs 46 kg more or weighs 100 pounds less than the original, depending on which article you believe.

I suspect that the battery is lighter than the engine, but the complete system is heavier than what it replaces, but that's just a guess.