Differentiating 240bhp 560SE motors from 300bhp motors...

[hydra]

Hey all,
I'm in the market for a used 560 engine to install in my W107, and I've got some questions:

First and foremost, how does one distinguish a low-output 560 from a hi-output 560? Dropped by my friendly MB Tech today, and according to the Bosch directory, the 300bhp engine is RB # MB1128, whereas the 238bhp engines are either RB # MB1130 or 1172. The 1128 was made ONLY between 10/85 to 08/87. All the aforementioned engines are M117.968's... I checked out an engine he happened to have lying around, and I couldn't find any evidence of this RB code nonsense... Now my question is, how can I best distinguish a 240bhp engine from a 300bhp engine? Are there any external clues to guide me? Secondly, what exactly is the difference between the two? I'd really appreciate your help on this.

P.S. I am located in Lebanon, where the majority of used cars and parts come from Germany and Switzerland...