  The predictive power of the NJL model is considered in the light of a novel
strategy to handle the divergences typical of perturbative calculations. The
referred calculational strategy eliminates unphysical dependencies on the
arbitrary choices for the routing of internal momenta and symmetry violating
terms. In the present work we extend a previous one on the same issue by
including vector interactions and performing the discussion in a more general
context: it is considered the role of scale arbitrariness for the consistency
of the calculations. We show that the imposition of arbitrary scale
independence for the consistent regularized amplitudes lead to additional
properties for the irreducible divergent objects. These properties allow us to
parametrize the remaining freedom in terms of a unique constant where resides
all the arbitrariness involved. By searching for the best value for the
arbitrary parameter we find a critical condition for the existence of an
acceptable physical value for the dynamically generated quark mass. Such
critical condition fixes the remaining arbitrariness turning the NJL into a
predictive model in the sense that its phenomenological consequences do not
depend on possible choices made in intermediary steps. Numerical results are
obtained for physical quantities like the vector and axial-vector masses and
their coupling constants as genuine predictions.
