Present paper aims to analyze the influence of certain parameters specific to the distribution systems on a truck engine performance. The research is focused on how the change in shape of lobes of a camshaft can influence the vehicle functional parameters. It was considered a   non-variable fuel distribution system which represents by itself the controlling part, needed to move the poppet valves in order to ensure engine operating cycles. There have been compared results obtained in case of different profiles of lobes, taking into account the accelerations during movements, in order to obtain minimum inertia of the distribution system components. By increasing the total height of the lobes, it was observed an increase in engine power and torque. Also, the intake fuel efficiency was improved by approximately 4%. Furthermore, engine fuel consumption reached higher levels in case of modified camshaft.