A fluid end assembly for a high pressure pump receives a fluid from a fluid supply manifold and supplies the fluid to an outlet manifold. The assembly includes a housing with a removable suction module. The housing has a plunger bore to receive a reciprocating plunger, a suction passage intersects said plunger bore, and a discharge passage intersects both said plunger bore and said suction passage. The removable suction module has an inlet passage.