On December 11, 1996, at 1745 central standard time, a Luscombe 8E airplane, N77974, was substantially damaged during a forced landing near Ardmore, Oklahoma. The airplane, owned and operated by a private individual, was being operated under Title 14 CFR Part 91. The commercial pilot and his passenger were not injured. Visual meteorological conditions prevailed for the personal flight for which a flight plan was not filed. The local flight originated approximately one hour prior to the accident. The pilot reported to an Oklahoma Highway Patrol officer that he had been performing touch and go landings at the Ardmore Downtown Executive Airport. He further reported that the engine lost power while on initial takeoff climb from runway 17, and he elected to return to the runway. He added that the airplane touched down long and overran the end of the runway impacting a drainage ditch. The airport manager stated that "the pilot acquired the airplane a couple of weeks earlier and had been flying the airplane almost on a daily basis." He added that the airplane's 85 horsepower engine had been replaced with a 150 horsepower Lycoming engine "which drastically improved the climb performance of the airplane." The fuel system on the 1947 vintage airplane had also been modified by the addition of new fuel cells. Another witness at the airport reported observing "black smoke coming out of the exhaust stack as if the engine was running very rich." Examination of the airplane by the FAA inspector revealed that both main landing gear separated from the airframe. The engine firewall and the bottom of the fuselage sustained structural damage. The FAA inspector confirmed that the engine and fuel system of the airplane had been modified by an approved STC. The reason for the loss of engine power could not be conclusively determined. Repeated attempts to obtain a completed "Pilot/Operator Aircraft Accident Report" (NTSB Form 6120.1/2) from the pilot/owner of the airplane were unsuccessful.