An air dispensing duct that can be used in an oven to heat or cook food products passing through the oven on a conveyor. The air dispensing ducts comprise a cover plate and at least one columnating plate, and a plurality of orifices disposed on the cover plate and the columnating plate. The orifices are larger than those of the prior art, which advantageously, and counterintuitively, provides forfaster cooking of the food product.