Cylinder head flow #

[Bill Baer]

The answer is yes the unshrouding of the valve with a larger bore usually results in more air flow.
How much depends on the valve lift ,port shape , port volume and probably a number of other factors.(type of intake manifold amongest others comes to mind.)
The only way to know for sure it to test the head on a flow bench with two different diameter flow (cylinder) fixtures.
Perhaps someone out there has experience with heads/bore confiburations simular to yours.
Good Luck!