Conversion efficiency, durability and pressure drop of automotive exhaust catalysts are dependent on the flow distribution within the substrate. This study examines the effect on flow distribution using substrates which feature contoured front faces. Three ceramic contoured substrates of equal volume were assessed. Two of the substrates were cone shaped with different cone angles and one had a dome shaped front face. Pressure drop and flow distribution was measured for a range of flow rates and substrate positions. Computational Fluid Dynamics (CFD) simulations were also performed to provide insight into flow behaviour. It is shown how a contoured substrate can provide improvements in flow uniformity and pressure drop when compared to the case of a standard non-contoured substrate.