An injector bore insert includes a proximate portion adjacent to a combustion face and a distal portion including an upper threaded outer diameter. The injector bore insert further includes an angled conical collar, a remote threaded portion along an upper bore portion, a circumferential slot extending distally from approximately the combustion face, and one or more sealing regions. Each sealing region is positioned on the injector bore insert to facilitate sealing between the injector bore insert and a cylinder head of an internal combustion engine.