On April 1, 1996, at 1449 mountain standard time, a Stafford RV-4 home built, N84PS, nosed over in a field near Longmont, Colorado, during an emergency landing following a complete loss of power. The two pilots aboard received minor injuries, and the aircraft sustained substantial damage. Visual meteorological conditions prevailed for the local area personal flight operating under Title 14 CFR Part 91. No flight plan was filed. The flight originated from Greeley, Colorado, (GXY) approximately 54 minutes prior to the accident. The pilot said that at the time of the flight's departure, the airplane had 11 gallons of fuel on board. According to the pilot, after arriving in the Longmont area they conducted three touch-and-go landings and were on a cross wind leg for a full stop when the engine "abruptly" quit. The pilot said three restarts of the engine were attempted without success, and he conducted a forced landing to a plowed field. During landing roll, the right main landing gear collapsed and the aircraft nosed over. Following the accident, two FAA inspectors examined the aircraft on two occasions. The first examination took place the day of the accident. According to the attached statement provided by the FAA inspectors, they found no evidence of fuel in or around the aircraft. In addition, in a statement made to the FAA inspectors, the pilot stated he should have had approximately 12 gallons of fuel on board at the time of the accident. The same inspectors returned the following day, April 2nd, and at that time found fuel in the left tank. In addition, the right magneto was inoperative. This was attributed to impact damage by the inspectors. No other evidence was found to prevent the engine from operating. A review of the O-360-A1D engine performance information was conducted. According to the Lycoming manual (page attached) the engine at 75 percent power (2450 rpm) burns approximately 10.5 gallons per hour. A review of pilot information produced evidence that the pilot's medical certificate and his biennial flight review were not current. Attached is information provided by the pilot to document a current biennial flight review and medical certificate. Both were executed after the accident date. Also, according to the information provided in the Pilot Operator Report, the pilot had not flown in the previous 90 days prior to this flight. The pilot/passenger in the rear seat owned the airplane. He was a certified flight instructor (CFI), and was current in all respects. The flying pilot said that he was the pilot in command and that the CFI was a "passenger." The rear cockpit in this aircraft was equipped with aileron and elevator controls only. There are no rudders, throttle, mixture control, flap control or instruments.