Modeling the flight conditions of an aircraft that utilizes an airbreathing propulsion system necessitates a method to account for the increase in energy introduced into the flow. Current methods for modeling engines either assign fixed conditions on flat faces on the intake and exhaust through a manual process with the use of external models or attempt to model the flow through the engine within the simulation using complex and computationally expensive geometry and solvers. The method presented attempts to provide an intermediate option to model airbreathing engines through coupling the intake and exhaust boundary conditions with a parametric engine model. This enables the intake conditions within the finite volume simulation to assign the exhaust boundary conditions as the solution iterates, allowing for engines to be dynamically simulated in transient cases and for continuity in the simulation to be better maintained. This method of modeling airbreathing engines could also prove useful in nacelle optimization studies and in modeling aircraft with long engine intakes. The NASA Common Research Model and an axisymmetric nacelle geometry are used to demonstrate the functionality of the developed coupled engine model and its implementation in a finite volume solver.