An effective flow deflection by means of rear wings is essential in providing sufficient traction for high-performance racing cars. This is especially the case for acceleration phases and turning maneuvers where critical inertial forces are present. This study investigates a realistic racing car model (1:3 scale) that exhibits a relatively short distance between head restraint and rear wing cascade. Furthermore, no specific passive measures are taken to condition the flow downstream of the driver so that the rear wing inflow is generally determined by the geometries of helmet and head restraint. While the minimal size of the latter is limited by competition regulations due to safety issues, an enlargement of the device is not prohibited. The aim of this experimental study consists in the identification of a head restraint size that ensures the safety of the driver and does not negatively affect the aerodynamic properties of the racing car model. In order to do so, wind tunnel tests are performed where the racing car model is equipped with head restraints of different size. The thus induced wall pressure distributions on the three rear wings are assessed in multiple longitudinal sections and areas of separated flow are visualized by means of UV active tufts. Additionally, force measurements are conducted with the aid of a lever balance to gain insight regarding the influence of the studied head restraint-rear wing interaction on aerodynamic coefficients. While doing so, various side-slip angles as well as Reynolds numbers relevant to the race phases stated above, are evaluated.