In a Six cylinder Inline Engine, it is possible to choose any one out of 120 possible firing orders. Selection of a particular firing order will influence the engine performance in respect of Torsional vibration amplitudes. Air mass flow inducted by the engine and degree of utilisation of pulse energy at the Turbine in case of Turbocharging. With change in firing order from 1-2-4-6-5-3 (originally designed) to 1-5-3-6-2-4 (modified for this work) engine could be effectively subjected to exhaust gas Turbo-charging for boosting the power upto 40%. Cumulative Torsional vibration amplitudes could be substantially reduced and benefits such as slightly improved fuel economy could be derived under the new firing sequence.