Need help with push-in style speedo cable at trans

I have a 1965 Chrysler New Yorker with a speedo cable that has the 5/8" nut at the instrument head and a push-in/clamp-retained end at the trans (TorqueFlite). The other type, 7/8" trans nut, are easy to find but not this one. Does anyone know if the inner cable itself can be interchanged while retaining the same outer sheath? Length appears to be about the typical 63". Better yet, does anyone know where I can get a new one complete or even a used set?

The inner swaps like any other.I just changed the one in my 65 B body.Got a universal at Advanced measured it and cut.Rocky