Numerical modeling of scramjet combustor flow field, which is turbulent and reacting, has been carried out using point implicit finite volume method. The numerical procedure is based on the implicit treatment of chemical source terms by preconditioning and solved along with unsteady turbulent Navier Stokes equations explicitly. The time integration uses three stage Runge-Kutta method. An eight-step hydrogen-air finite rate chemistry model is used to simulate the reacting flow field. Stiffness resulting due to chemical source terms has been minimized and CFL equivalent to that of non-reacting case has been achieved. Reacting code is validated against a standard coaxial jet experiment and demonstrated for a hydrogen strut injection in to supersonic airflow.