Australian W123 280E Timing

[cheezels]

Hi
Just joined the forum, so hello and g'day.
My teenage son has a 1977 W123 280E. He absolutely adores the car but she's running a bit rough.
We have purchased new plugs, leads, distributor cap, rotor and points so hopefully that will cure the rough idle.
I have a timing light but can't seem to find definitive timing information.
Is the timing the same as Euro and USA engines? (But my research reveals even these engines have timing differences)
What is the timing spec for the Australian M110.984 engine, please?
Also, what horsepower does the Australian engine version have. I have read 180 hp in various threads but in other threads there's a suggestion 140 hp is the rating.
Anyways, hope someone can straighten me out