A deheader valve is fitted onto an existing or new coke drum by initially positioning the body and valve, and then raising the valve to mate with the flange using a lifting device other than a chain fall. The vertical positioning of the deheader valve is preferably accomplished with a hydraulic or pneumatic piston, winch, scissor jack, ratchet jack, screw jack, and so forth. The distance traveled by the valve using these devices is more than 2 cm, commonly at least 20 cm, and in some installations up to 40 cm or more. In retrofit situations an oil inlet is provided in a side wall of the drum above the bottom drum flange.