Abstract: A flush valve is adapted for placement through a hole in the bottom of a toilet tank. The valve seat has an axis with a lower section adapted to extend through the hole and an upper section defining an opening generally perpendicular to the axis. A first sleeve communicates with a central channel in the upper section. A valve elbow has a second axis with an overflow section and a second sleeve registerable with the first sleeve to provide fluid communication between the overflow section and the (central channel) an associated method includes injection molding steps wherein first and second core pins are removed laterally and the second sleeve is inserted into the first sleeve to provide fluid communication between the overflow section of the valve elbow in the central channel of the valve seat.