On August 19, 2006, about 1505 eastern daylight time, a homebuilt Ginny B airplane, N349E, was substantially damaged during a forced landing, after it experienced a loss of engine power in cruise flight near Shiloh, New Jersey. The certificated private pilot sustained minor injuries. Visual meteorological conditions prevailed and no flight plan had been filed for the flight that departed Alloway Airfield (NJ02), Alloway, New Jersey. The personal flight was conducted under 14 CFR Part 91. The airplane was owned and built by the pilot. He reported that he was in the process of completing the airplane's phase I, 40-hour flight requirements. Approximately 35 minutes after takeoff, while in cruise flight, the engine began to experience a power loss, that was followed by an oil leak, and blue smoke. The pilot performed a forced landing to a soybean field; however, during the landing, the airplane's propeller, cowling, rudder, and wings were damaged. The airplane was equipped with a modified automotive engine. The pilot reported that postaccident examination of the engine revealed that it had overheated; and had expelled its liquid coolant overboard, through the overflow reservoir. The specific reason for the overheating condition could not be determined. The reported temperature at an airport that was located about 14 miles southeast of the accident site, about the time of the accident, was 82 degrees F.