An extrusion die is processed to alter the flow of extrudable material through the die by collecting data reflecting flow variations across the face of the die, constructing a graded resistance flow restrictor utilizing the data, and forcing an abrasive machining medium through the flow restrictor and die with the flow restrictor being arranged to deliver higher abrasive flow through die portions initially exhibiting low extrusion rates, the resulting die being useful for the manufacture of ceramic honeycomb bodies exhibiting a reduced incidence of shape defects attributable to die flow variations.