We have applied a theoretical equation of state for fluids, modeled by a square well with an embedded point tetrahedral octopole, to predict the behavior of real substances. This equation has four disposal parameters: depth, range, diameter, and octopole moment strength. With this simple four-parameter equation, we are able to predict with reasonable good accuracy the thermodynamics of methane and carbon tetrafluoride. This equation is able to reproduce the experimental vapor-liquid phase diagram and the saturation pressures, except in the critical region. Very good predictions of this equation for the speed of sound are found for both substances in the gaseous region. The selected substances are just an example of the adequacy of this equation to model the behavior of real polar fluids whose molecules have tetrahedral symmetry.