UPDATE 2007-01-13
The engine works!
The engine is finally put together and we tested it a bit. There's some problems to solve: The fuel pump seems not to work so we had to pour gasoline straight into the carburetors. Also there's some issues with timing. But the engine runs!
Download the video of the first attemps to get it to run (Windows media, 6.15 Mb).
The test rig
Great fun! (Actually there was propably a bit too much oil in the mixture.)