A modular lighting system for controlling light output and direction in a pole top luminaire includes a base. Lighting modules which have LEDs mounted on a heat sink include pairs of heat pipes extending from the heat sink plug into the base. Openings in the base receive the heat pipes to support the lighting modules in a desired orientation, enabling location specific customized orientation. The assembly allows universal replacement of pole top luminaires with efficient LED light engines, yet without need for custom parts, thus enabling a wide variety of applications for the lighting modules.