A drive assembly for connection to the polish rod of a reciprocating pump includes a support frame fixed in proximity to a wellhead. A linear actuator includes a lower portion fixed to the support frame and an upper portion supporting two pairs of direction altering cable guides thereon. Four lengths of cable each include a first portion substantially anchored to relative to the polish rod by a pump bracket, a second portion substantially anchored to the support frame by an anchor bracket, and an intermediate portion extending through a respective one of the direction altering cable guides on the upper portion of the linear actuator between the first portion and the second portion.