Conveyor ovens for cooking food according to various embodiments include one or more passive tubes in a plenum positioned opposite one or more burner tubes, wherein the passive tubes have outer walls with apertures therethrough. In some cases, a burner assembly for a conveyor oven includes at least one burner tube extending into a plenum and positioned to receive at least a portion of a flame emitted by the burner assembly, wherein a rifling plate extends through the burner tube and is slidingly positioned within the burner tube. Also, in some cases a baffle in a plenum of the oven is positioned opposite the burner tube and defines a fluid conduit having an entrance into which air heated from the burner tube is received and an exit separate from the entrance and through which air is discharged.
