Three-dimensional numerical calculations of Heliac equilibria are presented. The results indicate that finite-β distortions in the flux surfaces can arise because of the presence of low order rational surfaces within or near the plasma. These distortions arise as a result of non-linear beatings between the toroidal shift and the helical components of the magnetic field. Reducing the toroidal shift by increasing the number of field periods and/or the aspect ratio improves the equilibrium β-limit.