I don't think that you'll have a problem using the speedo cable , as they sell replacements that aren't brand specific. You'll need the proper little gear that goes on the end of the cable in the trans , though.
Have you looked for a square chebbie speedo at your local junkyard? They sell digi speedos , which you can mount where you want , then put pictures of your loved ones in the old speedo hole!
good luck with it !!