Oscillating head with contiguous counterweight

A prime example of an application for a head with contiguous counterweight is a sucker rod reciprocating pump whose circular arc head is contiguous with a counterweight and is pivotably connected to the pitman arm, crank arm weight, and speed reducer. The pitman arm is substantially horizontal and the crank arm to wrist pin phase angle is about 70-90 degrees. Auxiliary counter weight extends from the head weight on a stinger and the head weights are adjustable. The head weight diameter is either constrained within the circular arc head's outer diameter or can be larger. The upper pitman bearings are outboard on the equalizer which is integral with the head. The center bearing of the head is outboard on the rectangular sampson post. The head counterweight increases permissible load on a speed reducer. This example use of a head with contiguous counterweight has can be configured to utilize beneficial embodiments for adjusting sampson post height and pitman arm length; and for changing the stroke length without removing the wrist pin from the crank weight hole.