A fluid distribution insert adapted to be received within an inlet header of a fuel cell assembly. The fluid distribution insert includes a hollow insert with a first end and a second end. An inlet is formed at the first end of the hollow insert in fluid communication with a source of a reactant gas and adapted to receive the reactant gas therein. An outlet is formed intermediate the first end and the second end. The outlet is adapted to deliver the reactant gas to a plurality of fuel cells of the fuel cell assembly, wherein the hollow insert delivers the reactant gas to the fuel cells in a substantially simultaneous and uniform manner.