Pilot on night cross country flight with clear, very cold weather, experienced total loss of engine power while cruising at 7500 feet MSL. Approach control gave position of closest field, but pilot elected to continue to destination which was five miles farther. When pilot realized he could not make intended destination, he accepted vectors to closest field. Pilot did not think that field could be made and elected to make a landing on highway. The acft hit a light pole while maneuvering for a short final approach with the highway. Engine inspection could find no defects. Engine ran well and produced normal power in test cell. The pilot reported that there was only 2200 RPM at full throttle both on the ground and in cruise. He further stated that he was not utilizing the winterization kit. The maximum oil temp was 80 degrees F. According to the engine manufacturer, operation at severe temperatures can allow minute ice particles to collect on the carburetor inlet screen and block some or all of the fuel flow.