What engine??

[simontjell]

Hello,
I just bought a 1981 250 and I'm very happy for it.
One thing bothers me though, and it's a bit embarassing:
I'm not sure which type of engine is under the hood.
Here is what I know:

It was not the engine that was originally in the car.
It's a petrol engine - haven't tested it with diesel though
It has 6 cylindres.
I've been told that it has electronic injection.
An 'E' was put in front of the '250' letters on the back of the car when the engine was replaced.
These two numbers are written on the engine:
123.223 (bottom) and 123.016 (top)

Is that enough information to tell which engine I have or do I need to go look for more numbers/take photos?

Thanks in advance,
Simon Tjell (Denmark)

 

[heckflosse]

If i'm correct in what I remember the 250 engine number was 123.xxx.
The only two 6 cylinder engines put in the W123 series was the 250 which is a single over-head cam and the 280 which is Double OHC.