SPECS: Displacement: 0.15 cu in (2.49cc) Crankshaft Thread: 5mm (.197") On-Center Mounting Holes, Front to Rear: 11mm (.433") On-Center Mounting Holes, Side to Side: 31.4mm (1.24") Back of engine(recoil)to front of drive washer: 73.2mm (2.88") Height: 97.3mm (3.83") Exhaust Port Diameter: inner - 9.9mm (.392") outer - 13.0mm (.512")