Hmmm...
Several issues here:
1) As I was taught one day, the only reason internal combustion engines have transmissions is that the ever important torque varies with engine RPM, therefore you need a transmission to keep your power and torque available to you. This begs the question of why he needs or wants a 4 speed. Diesel electric locomotives (diesel generator powering electric motors) don't have transmissions as we know them in the classic sense because they don't need them. Full torque is achieved the moment you energize the motors, as I understand it.
2) Are you talking full electric or hybrid? If full electric you've got quite a chore ahead of you. In a vehicle in which we can't seem to find adequate space to install stereo speakers, and one in which only a bag of junior sized golf clubs will fit (and then only when you remove the spare!) I think your battery space will be limited. And in a vehicle already a bit on the heavy side you've got quite a weight issue to deal with.
3) Why on earth would anyone consider this project? I agree with Tom, he's pulling our leg. If you want an engineering exercise, you could choose a vehicle or platform somewhat newer then the 113; somewhat less expensive both for parts and for your core; and one that is populating the salvage yards across the USA. A 34-43 year old low volume German roadster? I don't see it happening any sooner then the supercharger on the M130 motor.
4) You could probably have a fiberglass body molded like a 113 and put over a golf cart for a lot less money and effort...
Michael Salemi
1969 280SL
Signal Red w/Black Leather
Restored