In the framework of a dynamical gluon mass model recently developed, we investigate the effects of two essential parameters in the description of elastic $pp$ and $bar{p}p$ data at high energies: the soft Pomeron intercept and the dynamical gluon mass. By considering relevant numerical intervals for both parameters and fits to the experimental data up to 1.8 TeV, with good statistical results, we discuss the predictions of the physical quantities at the LHC energies (7 and 14 TeV). We conclude that these quantities are sensitive to those variations and the predictions are correlated with the intervals considered for both parameters. This conclusion puts limits on the reliability of QCD inspired models predictions at the LHC energies, mainly those models with ad hoc fixed values for the mass scale and the Pomeron intercept.