Methods and devices for attaching fluidic or other interfaces to an extruded honeycomb body reactor are disclosed, the method including providing a mechanical interface to the honeycomb body without encircling the honeycomb body, and mounting a fluidic or other interface to the mechanical interface. Alternatives for the mechanical interface include trenches on opposite sides of the body, one or more trenches on the same side of the body, and blind holes with screw anchors.