1968 barracuda speedometer cable

Original 68 Speedo's have a push in with white plastic clip connector.

Either your's was replaced once or maybe leftover 67 parts (very doubtful).

But if your's screws into the back of the speedo, you need the one pictures with the screw at both ends.

This is what the 68 and up cable's ends look like:





Here's the back of a 68 speedo: