I have a twin choke webber fitted and the pipe work fitted on YOUR inlet manifold doesn't exist on my inlet manifold.
looking at the inlet Manifold block side there are four holes obviously for each bore and one rectangular which continues to a hole in the front of the inlet manifold, the rectangular hole also exists on the block. This is the one which I have/believe was the point for the servo and breather but this may be incorrect as there is also another hole above it for something ??