Tube assembly-fuel supply line from 9C166 housing to frame line. Used with 9N320 fitting to connect to 9C166 housing. Connects to center port on side of 9C166 housing, Diesel 6.0L. For Engine Serial numbers Before 6240241 (2/4/2004 Indy) & engine serial number 117667 (2/13/2004 Huntsville)