The energy-momentum relationship is obtained in para-Lorentzian dynamics. It is shown that the well-known correspondence rule for the operators energy and momentum holds in any inertial system if it is assumed to hold in the preferred reference frame. The new Dirac equation is obtained. Some qualitative features of the new theory are given; one of then is the spontaneous appearance of conserved-vector and nonconserved-axial weak currents. Finally one evaluates the convenience of further developments of the present theory in view of (...) the excellent agreement of QED with experiment. (shrink)