1966 C 10 should not have a 235 it should have a 230.
According to the GM archives
https://www.gm.com/content/dam/compa...olet-Truck.pdf
the base engine.
That is unless someone has cobbled (I don't know what the German term is) a 235 into a later truck. Quick iD is a 235 distributor is about half way back on the engine, a 194.230/250/292 distributor is up close to the front.
As far as I know the blocks and even head gasket are the same. Just the wonky integrated head that someone dreamed up.
You can find specs by the year on Most Chevy engines by clicking on the right year and model.
https://www.gm.com/heritage/archive/...tion-kits.html
The Rock auto cheat sheet to see what fits what helps there. By clicking on a parts number you can see what else a part fits.
The O'Reilly Autoparts website will do that in more detail but I am not sure if it will open easily in Germany and giving a tutorial for it would be a post by it's self.