  In this work we propose a preliminary seismic investigation of $\delta$ Scuti
stars in the Pleiades cluster, focusing on potential diagnostics of convection
and core-overshooting. Taking into account the effect of fast rotation in the
modelling, we compare observed frequencies for 4 $\delta$ Scuti stars with
radial linear instability predictions. A satisfying agreement is reached
between the predicted ranges of unstable modes and those derived from
observations for ``low-mass'' stars ($\sim 1.55 M_{\odot}$). However, a strong
disagreement is found for ``high-mass'' stars ($\sim 1.77 M_{\odot}$), whatever
the mixing length $(\alpha)$ value. These results are compared with previous
ones obtained for Praesepe.
