intake manifold

Hi,

I am trying to install a new Edelbrock 7111 intake manifold on my Olds 350 engine. With the manifold came 2 cast iron blocks. You have to fit these in the to center ports, But they won't fit. Is this normal, Do you have to machine them? I bought intake gaskets from Mondello which will block off automatically those 2 center holes. Do I need to fit those iron blocks????

Thanks

Anton

The Netherlands