A method of continuously manufacturing a high viscosity polyalphaolefin product by introducing a monomer and an ionic liquid catalyst together into a reaction zone while simultaneously withdrawing from the reaction zone a reaction zone effluent that contains the high viscosity polyalphaolefin. The reaction zone is operated under reaction conditions suitable for producing the high viscosity polyalphaolefin product. The preferred high viscosity polyalphaolefin has a kinematic viscosity exceeding about 8 cSt and is the reaction product of the trimerization, oligomerization, or polymerization of an alpha olefin or a mixture of one or more product thereof. The high viscosity polyalphaolefins are useful as lubricants or lubricant additives.