A solid cluster of 923 atoms bound by pairwise Morse interactions is the model for analyzing thermodynamic properties and phase equilibria in moderately small systems. The range of the potential is chosen so that the free energies of the icosahedral and face-centered cubic (fcc) structures are similar, enough so to allow a phase change between them. Statistical parameters of the cluster are determined for the two structures from their configurational entropies and pair interaction energies. The heat capacity and entropy of this cluster are calculated for conditions in the region of the phase change between the two solid forms, as well as away from this region. The configurational contribution to the thermodynamic properties is small relative to the vibrational contribution, but dominates the differences between free energies of the two phases. The configurational contributions to the thermodynamic properties become relatively more important for liquid clusters.