At this point in time, almost every speedo cable kit you find will be the 80" universal fit item. You can use your existing cable housing and cut the inner part (cable) to fit. These kits should come with a plastic square end, with a dab of adhesive inside of it to apply to the end you cut to length, to make it square. The OEM production cables had that end squished into a tight square, which is probably preferrable, but unless you can find an OEM cable of similar length, the glue-on end is the only option. UNLESS you get into the replacement industry outside of the autl supplies and get into a speedometer/speedometer cable replacement supplier. Might look in the ads in a Mopar or Chevy enthusiast magazine for these ads. Seems like there is or was a place in MI where the owner originally worked out of his garage, who used to work "in the industry" and makes cables per application (as they all used to be available, not just universal). "Mopar Muscle", "Mopar Action", and "Super Chevy" are where I used to see those ads. Not sure of the pricing, but I heard great reviews of his work.
You might find the correct length for your application in the Chrysler parts book, as it was listed that way in the GM parts books "back when". As noted, you might not get something of the exact length already made-up and ready for installation, but a few inches longer is just fine.
Any cable should come pre-lubed, too. AC-Delco had the old ST-___ speedometer lube. A "lifetime supply" in a tube.
KEY thing to diagnose is why the orig cable failed! PLUS check the speedometer gears are still in good condition and don't need to be replaced. It would be good to put some sort of cover over the adapter plug on the tailshaft housing, but there should not be any active atf pressure to that point, just splash oiling of the gears. IF there is a good bit of oil in the cable housing (atf), there is a simple lip seal inside of the plug that probably needs replacing.
I generally like Rock Auto for their catalog listings. They enable me to see what might be available from them or the local auto supply stores. BUT they are not the ONLY place to get things, as there is a whole 'nuther industry that serves the restoration industry and enthusiasts of such, usually at a bit higher prices. Places which usually advertise only in those targeted publications. Up to and including Hemmings Motor News (or their several monthly magazines now).
Enjoy!
CBODY67
