Recent experiments have demonstrated the first preparations of stereochemically-variable polysiloxanes that have sufficient regularity to undergo large amounts of chain crystallization. The specific polymer, poly[methyl(3,3,3-trifluoropropyl)siloxan], had been prepared from various proportions of cis and trans cyclic trimers using special catalysts, and a number of its properties documented. The present computational investigation was carried out to interpret these results, using Monte Carlo methods to generate representative sequences and to study the possible packing of such sequences into crystalline regions in multichain systems. The quantities of particular interest were the nature of the stereochemical sequence distributions, degrees of crystallinity, melting points, interfacial free energies, and moduli (calculated on the basis of the crystallites acting as cross-links in an elastomeric structure).