I have a question on intake gaskets

Hi to All
I have a question on intake gaskets on a 68 327 chev.
I feel pretty dumb to ask this but what the ha. What are the metal reducers on the center water port on the head do. Can you leave them out or what. I have alway wondered about this and now I just removed the intake on my motor and there were no reducers on the center port but the new Eldel gaskets come with two different sets with the gaskets I got # 7201.
What should I do and which one to use is my question or do I leave them out.
The motor is in a 68 chevelle

The metal pieces are designed to block off the exhaust gasses that pass in the passage under the carb, or limit depending on the size of the hole or no hole in them. A colder air fuel charge adds horsepower, but with no heat on the air fuel mixture cold weather performance will suffer....

So with what your are saying which would give me the coldest air fuel charge?
With the reducers or with out.
The car is only run in the summer.
Stored all winter
Thanks
Carnut