I am trying to find the what the meaning of the code numbers on the side of the engine block mean. I have searched the web and contacted my local MB dealer. So far I have found nothing. I know the engine in the car is not the original, and I am trying to find out what it is.
The numbers appear on the left side of the block just above the oil pan.
Here are the numbers I am trying to ID.

23G 85
Mercedes Benz
602 011 07 01

I tried to attach a photo.

Any I have a source?
I have looked at Adstico and German Star sites, but they do not go into detail, also there are some conflicts between the sites information.

Thanks