Take a look at the picture Tony posted.
In the center of the intake port is part of the head casting that the head bolt goes through. It is basically round, it does not separate the two intake valves behind it. A trick to improve intake flow a great deal, is to mill the casting out of the port. A stud is used instead of the original bolt, with the stud protruding into the port only by enough to install a nut. The flow over the nut does not disturb intake flow nearly as much as the casting did. The hole left above the port where the bolt went through is closed off using a plug.
This should improve the power of an injected engine as well.
