On May 14, 1997, at about 1240 eastern daylight time, N4992V, a Cessna 180J, owned and operated by the private pilot, sustained substantial damage shortly after takeoff when the pilot reported a loss of engine power and crashed on Interstate 89, about one-half mile east of the Lebanon Airport, Lebanon, New Hampshire. The pilot and sole occupant was not injured. Visual Meteorological conditions existed and no flight plan was filed. The flight was conducted under the provisions of 14 CFR Part 91. According to the pilot, he was going to Lake Sunapee to practice water landings. At 400 feet after takeoff, the engine went silent. The pilot stated he headed for Interstate 89 to make an emergency landing. As he got closer, he noticed a lot of traffic. The pilot landed the airplane on an embankment off the right side of the highway. The airplane touched down and continued for about 100 feet on the embankment before the airplane flipped over onto the highway. The aircraft had not been flown for 9 days prior to the accident. An inspection/examination of the engine was conducted at Teledyne Continental Motors on December 11, 1997. Present during the examination was the National Transportation Safety Board (NTSB), the Federal Aviation Administration (FAA), and the Continental Motors. All valve covers, throttle and intake pipes were returned loose. All engine mounts were broken and the number three intake pipe was damaged from impact. The oil sump was dented upward however there were no punctures observed. One rear induction elbow was damaged from the impact. The crankshaft propeller flange was visually examined and no cracks were observed. In order to do a test run, the engine mounts and loose parts were mounted back on the engine and the induction elbow was replaced with a slave pipe. Exhaust stacks, temperature probes, and an adapter for the propeller governor pad were installed for testing. Engine startup was immediate and the engine ran smoothly. After the warm up, the engine was run to 2100 RPM for a magneto check. Both magnetos had a 50 RPM drop. The engine was then run to full throttle for 10 minutes. The engine produced the rated RPM and horsepower. The engine was then run at cruise power for an additional 15 minutes and no discrepancies were found.