Molecular dynamics simulations have been performed on a single hexane molecule fixed in a single shape, defined by a rotation angle phi about the center C-C bond, in a collection of 256 rigid particles interacting with each other through the Gay-Berne potential. The system is in a nematic liquid crystalline phase. Seven separate simulations were done, in each case with the hexane in a different shape, and the results are used to test theoretical models for conformationally dependent potentials of mean torque, which have been used to calculate averaged values of internuclear dipolar couplings. The results suggest that the truncation of the potentials of mean torque at second-rank terms is a good approximation when calculating dipolar couplings, but that there are inaccuracies in the shape dependence of the potentials.