Valve member including cavity, and related assemblies, systems, and methods

A valve member for a high-power pump, the valve member comprising:

• a valve body defining a valve body axis, an axial cross-section transverse to the valve body axis, and a radial cross-section defined by a radial plane extending through the valve body and coextensive with the valve body axis, the valve body including:
• a valve head having:
• a substantially circular axial cross-section including a radially outer perimeter;
• a seal engaging surface positioned to receive a valve seal, the seal engaging surface being associated with the radially outer perimeter and having a first axial position relative to the valve body axis;
• an exterior side facing in a first direction along the valve body axis;
• an interior side facing in a second direction opposite the first direction;
• and
• a cavity at least partially defining a cavity interior, the cavity interior extending between a cavity opening and a cavity end, the cavity interior extending from the cavity opening at a second axial position spaced from the first axial position of the seal engaging surface relative to the valve body axis and to at least an axial mid-point of the first axial position to the cavity end at a third axial position relative to the valve body axis, thereby to reduce mass of the valve member and substantially maintain strength of the valve head.