First intake valve and second intake valve for an engine cylinder bore within which a piston reciprocates are arranged side-by-side in a cylinder head for motion in unison along respective intake valve axes. First intake valve axis is nonparallel to the cylinder bore axis. A first intake valve seat for the first intake valve is disposed in a plane which is non-parallel to a plane which is perpendicular to the cylinder bore axis. First intake valve seat has a first semi-circumference toward a second semi-circumference of a second valve seat for second intake valve. At least a portion of first semi-circumference is closer, as measured along a direction parallel to the cylinder bore axis, to a plane passing through the piston perpendicular to the cylinder bore axis than is the second semi-circumference as measured along a direction parallel to the cylinder bore axis.

First intake valve and second intake valve for an engine cylinder bore within which a piston reciprocates are arranged side-by-side in a cylinder head for motion in unison along respective intake valve axes. First intake valve axis is nonparallel to the cylinder bore axis. A first intake valve seat for the first intake valve is disposed in a plane which is non-parallel to a plane which is perpendicular to the cylinder bore axis. First intake valve seat has a first semi-circumference toward a second semi-circumference of a second valve seat for second intake valve. At least a portion of first semi-circumference is closer, as measured along a direction parallel to the cylinder bore axis, to a plane passing through the piston perpendicular to the cylinder bore axis than is the second semi-circumference as measured along a direction parallel to the cylinder bore axis.

Methods and systems are provided for operating an engine in a two-valve diagonal blow-through mode during which a majority of blow-through is directed via a first intake valve positioned diagonally across a first exhaust valve in order to increase a distance of flow path from the intake valve to the exhaust valve.