An industrial furnace burner block assembly is presented herein. The assembly includes a mounting plate defining a fire tube extending there from. A plurality of tabs extend from the mounting plate and engage a corresponding groove or slot formed on a refractory burner block. The burner block includes four block sections that each allow for independent thermal growth during operation. The burner block also defines a center aperture collectively formed by corresponding internal surfaces of the independent block sections. A sealing ring is mounted within a groove in the burner aperture and is disposed in a sealing relation with an external surface of the firing tube. A tongue-and-groove connection assembly is formed on mating surfaces between adjacent burner block sections. The tongue-and-groove connection assembly and the sealing ring each provide a gas-tight seal that restricts gas bypassing.