An LED retrofit lamp for a projection headlight system comprises a heat dissipating body portion and a substantially rectangular substrate. A first LED group is mounted on a first surface of the substrate and a second LED group is mounted on a second surface. A support bracket is configured to engage longitudinal sides of the substrate to mechanically support the substrate in alignment with a central optical axis of the headlight system so that light emitted by the first and second LED groups parallel to the first and second surfaces illuminates corresponding top and bottom segments of a cooperating reflector with sufficient intensity for projection headlight system to form a beam having substantially homogenous light intensity.