We prepared a homologous series of achiral bent-core (BC) liquid crystals with different terminal alkoxy chain lengths, n (BC-n), and evaluated the helical twisting power (HTP) of the BC-n doped in a cholesteric liquid crystal. The BC-n molecules with longer terminal chains showed larger HTPs. To interpret this striking phenomenon, a stochastic dynamics simulation was performed to determine the distribution of the chirality order parameters (χ) for BC molecules with n = 8–16. The distribution of χ for each simulated conformation varied with n, and the variation tendency was different for molecules with n < 12 and n > 12 despite the linear relationship between HTP and n in the experiment.