Lubricant compositions comprise blends or mixtures of low viscosity, 3-8 cS e.g. about 5 cS(100.degree. C.), HVI lube basestock with higher viscosity, 15 cS+e.g. 30+ cS(100.degree. C.) HVI PAO lube basestock produced from slack wax by thermal cracking to alpha olefins followed by Lewis acid catalyzed oligomerization of the alpha olefin mixture to lube base stock. Blending these components in appropriate proportions produces lube basestock having viscosities in the range of 8-15 cS (100.degree. C.) from which material suitable for the formulation of 10W-30 automobile engine lube can be produced. The blends are notable for exhibiting high VI values greater than that of either component of the blend.