A cylinder block assembly for a reciprocating pump includes a block body having a piston chamber that receives a piston of the reciprocating pump. The cylinder block assembly has an outlet valve assembly positioned within the block body that is positioned in fluid communication with the piston chamber. An outlet valve retainer retains the outlet valve relative to the piston chamber. The cylinder block assembly includes an inlet valve assembly extending through a side of the block body to the piston chamber. An inlet valve retainer also retains the inlet valve assembly relative to the piston chamber. A discharge passage extends from the outlet valve assembly to another side of the block body. A portion of the discharge passage extends between the inlet valve assembly and the inlet valve retainer.