Pulsation in two Herbig Ae stars: HD 35929 and V351 Ori

New photometric observations of seven intermediate mass pre-main sequence d elta Scuti candidates are presented. The periods and pulsation modes are de rived for two of these stars, namely HD 35929 and V351 Ori. The comparison between observations and nonlinear pulsational models allows us to provide some initial constraints on their mass and evolutionary state. As an illust ration we discuss the use of periods to identify the mode of pulsation in t hese two stars and to have an independent estimate of their distances.