Abstract: A pumping unit or pump jack, of the walking beam type of class I geometry, is provided which is arranged to permit relatively efficient pumping of a well inclined to the vertical, by suitable selection of beam support configuration and location, horsehead size, configuration and position, and position of the beam support fulcrum and beam length. Also provided is an adjustable pumping unit arranged to relatively efficiently pump wells ranging from about 0.degree. to 45.degree. off-vertical, in that the pitman is adjustable in length and the angle of inclination of the longitudinal axis of the samson post is adjustable.