Abstract: A process unit for the zeolite-catalyzed conversion of light refinery olefins from an FCC unit such as ethylene, propylene, and butylene to gasoline boiling range motor fuels comprises at least two sequential, serially connected reactors connected in parallel to a fractionation section with at one or two fractionators for separating the reactor effluents into product fraction with an optional recycle stream or streams. The configurations according to this scheme allow the adjustment of reactor temperature and/or pressure and/or space velocity to be based on the reactivities of the olefin compounds present in the LPG streams so that the gasoline produced in each reactor will be separated immediately, to reduce over-polymerization of the gasoline in the low severity reactor and to ensure that gasoline formed in the low severity reactor will not be sent to the higher severity reactor e.g.