This is an NOS 1930-32 commercial headlamp wiring conduit. Unlike the passenger cars which used metal, the commercial trucks used lacquered wire loom with stainless ferrules crimped on the ends. The overall length of this conduit is 7-7/8 inches.
The pic above shows a close-up view of the end which is retained to the headlamp housing connector.
This view shows the ferrule end which goes into the radiator shell.