THE PLT DEPARTED AURORA, CO AT 1000 EN ROUTE TO GREAT FALLS, MT AT 8000 FT MSL. AT 1237 THE PLT ADVISED WORLAND FSS THAT THE ENG HAD LOST POWER AND HE WAS GOING DOWN. THE PLT SAID THAT ON FINAL APCH HE HAD TO PULL UP TO AVOID POWER LINES. THE ACFT STALLED AND NOSED INTO GROUND. THE CRASH SITE WAS 5 MI EAST OF GREYBULL, WY. THE FUEL SELECTOR VALVE WAS POSITIONED ON THE LEFT TANK. THE LEFT TANK WAS FOUND TO BE EMPTY AND THE RIGHT TANK WAS FULL. THE ACFT HAS 2 FUEL TANKS, EACH HOLDS 46 GALS (44 USABLE). THE DISTANCE FROM AURORA TO GREYBULL IS APRX 354 NAUTICAL MI. TIME EN ROUTE WAS APRX 2 HRS, 37 MIN. THIS COMPUTES TO AVERAGE 136.2 KTS GROUND SPEED. PERFORMANCE CHART FOR 8000 FOOT PRESSURE ALT GIVES A NUMBER OF POWER SETTINGS THAT WILL YIELD AVERAGE FUEL CONSUMPTION RATES BETWEEN 10.3 AND 17.8 GPH AND AVERAGE TRUE AIRSPEED BETWEEN 111 AND 151 KTS.