Unsteady gas flow in (3+1)-dimensions is studied and analyzed here using an optimal system of Lie symmetry vectors. The governing equations admit thirteen Lie dimensions space. An optimal system of linear combinations of these vectors was formulated to determine the most suitable combinations for solving the governing equations. Unique, double, triple and quadruple combinations were used here to detect analytical solutions. Adiabatic index effect on the attained velocity, density and pressure profiles was also studied. Analysis of the results showed that the velocity profile components increase throughout increasing a distinct spatial variable and throughout the increment of adiabatic index. For density and pressure distributions, analysis of some obtained cases leads to that both of them decrease throughout increment in spatial variable or adiabatic index as long as the solution is non-singular. In case of singular solutions at zero, a reverse result was obtained.