Disclosed herein is an implantable pulse generator for administering electrotherapy via an implantable lead. The pulse generator includes a housing and a header connector assembly coupled to the housing. The header connector assembly includes a connector assembly and a header enclosing the connector assembly. The connector assembly includes a support and a connector receptacle. The support extends at least partially about the connector receptacle and is at least partially responsible for having prevented injection molding material from entering the connector receptacle when the injection molding material was injection molded about the connector assembly in forming the header.