A contact module includes an overmolded leadframe with frame members separated by corresponding gaps and a removable insert coupled to a corresponding receptacle signal contacts. The removable insert has a main wall, end walls extending from the main wall and forming a receiving space therebetween, and a finger extending from the main wall in the receiving space. First and second channels are formed between the finger and the corresponding end walls that receive the contacts. The finger and end walls hold the lateral positions of the contacts during the overmolding process. The receiving space is filled with dielectric material during overmolding and the removable insert leaves a window in the corresponding frame member that exposes the corresponding receptacle signal contacts.