Need more spec's on the M116 engine

[retroguybilly]

I recently got my 420SEL running well, and am starting to understand why you guys are so enthusiastic about M-Bs. Manischewitz, that engine has a lot of power, and it's so smooth! Also, I'm not used to a large car that handles so well.

But I still have a couple of questions about the M116 motor. If I am not mistaken, this engine was produced from 1979 to about 1990 or so. Was it introduced with an iron block, and then later switched over to light alloy sometime during its production run? (Of course I know that my car has the M116.965 alloy block.) If so, when did that occur, and what are the differences between the two versions? Were any other significant changes made to the M116's specifications during its production run?

I'd appreciate it if somebody might know of a link that might cover this.