SPECS: Construction: Aluminum 1-piece crankcase, piston, cylinder head Bore: 23.0mm (0.906") Stroke: 18.4mm (.724") Horsepower: 1.2 BHP at 15,000 RPM Distance from remote needle to end of crankshaft: 4.5" (114mm) Distance from center of engine to drive hub: 2.0" (51.2mm) Distance from center of engine to end of crankshaft: 3.0" (76.3mm) Height from crankcase bottom to top of cylinder head: 3.3" (84.7mm) Height/crankshaft center to top of cylinder head: 2.7" (69mm) Width including mounting ears: 1.9" (48mm) Width not including mounting ears: 1.2" (32mm) Width between mounting holes same side: 0.69" (17.5mm) Width between mounting holes opposite side: 1.6" (40.5mm) Width between muffler mounting holes: 1.4" (36mm) Width of exhaust opening: 1.1" (29mm) Height of exhaust opening: 0.3" (7mm) Diameter of muffler body: 1.3" (33.5mm) Angle of muffler in relation to engine: 4° Weight: 272g (9.6oz without muffler) Crankshaft Thread Size: 1/4-28 Recommended Props: Break In: 11x6 Trainer and Sport Models: 11x6, 11x7 Scale Models: 12x5, 12x6 Practical RPM Range: 2,000 - 16,000 RPM (This engine will not turn this many RPM on the ground) RPM curve is when the engine unloads. REQUIRES Fuel with 5% - 15% Nitromethane and 18% (minimum) oil content (Most of the 5%-15% fuels we carry meet these requirements)