Hey Per - that sounds like good information. I have heard the two-stroke oil suggestion before. Have not tried this myself but now I will.
On the ignition timing, I believe this might be a good suggestion. I have fiddled with my ignition timing at some length, and I am in doubt as to whether the factory settings work properly on rebuilt engines, that may have slightly different timing due to planed heads etc. An experienced mechanic here in Holland told me he sets the timing simply by listening to the engine, how it responds to various settings. I set my timing last weekend using a timing light and the factory specs, and it ran less well than when I set it 'by ear'. I will try this Norwegian Method next time.
I reset the idle mixture to 4,5% last weekend as well, at 800 RPM. The car runs very well at those values.
Keep it coming!
Cees
Cees Klumper in Amsterdam
'69 white 280 SL automatic