Adaptor socket for CNG fuel injection

An adaptor socket (22) for connecting a gaseous fuel injector (24) to a port (4) in an intake manifold or flange (2) of an internal combustion engine, said socket being adapted to fit said port (4) and having a mounting aperture (31) for mounting a gaseous fuel injector (24) such that the gaseous fuel injector (24) can inject gaseous fuel into said intake manifold (2) via said port (4). The socket (22) further comprises means for enhancing the mixing of gaseous fuel and air within the intake manifold, said means comprising a lip or extension (46) provided or formed on the socket (22), said lip (46) extending into the path or passageway of incoming air within the manifold (2), upstream of a spray nozzle of the fuel injector (24).