An injector mount clamp for coupling an injector of an exhaust gas treatment system to an exhaust conduit of an engine while the conduit is in an installed position includes a resilient monolithic clamp body having an aperture extending therethrough and being shaped as a split collar having a first end spaced apart from a second end a distance allowing the clamp body to be transversely moved relative to an exhaust flow direction to a position circumferentially surrounding the exhaust conduit. An injector mounting boss is disposed on the clamp body and defines a passage that fluidly communicates with the aperture of the clamp body. The mounting boss has a mounting face configured to oppose the injector.