Unfortunately the engine still has a slight unbalance when running stationair. This is something I will take care off next year. I'm thinking of overhauling the carburetors and have them ultrasonic cleaned. In order to get the best fine tuning it should be done using a "kwik-kolom" - not sure how to translate this into English.
In any case the most importants jobs are done and the car is now in a technical good condition. I was recently informed I should also have looked into the bearings of the distribution - well, I leave that for the next round.