There is an electronic to cable converter, but I'd check to see what users of it have said. When I did this I learned it had a tendency for the needle to bounce at low speeds...this was a pretty uniform complaint and some said speeds below 30 mph or so were not dependable. I called the company who makes the unit and they told me they knew it was a problem but added not everybody complained about this. At that time they were crazy expensive.
I bought an electronic speedometer from SpeedHut and I'm going to make a face that resembles as much as possible the original one and adapt the original needle to work on it. If you do this, you'll learn the odometer will be the sticking point. I wasn't able to find any electronic ones with an odometer that looked like the original, but you might find one if you searched today.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end