Speedometer cable question....

Rusty, I am picturing in my head a unit that bolts to the trans in place of the speedo cable. It stays in the trans full time and a cable or electronic sensing unit screws into it. I remember seeing a unit like that from an aftermarket vendor, and I think it was for early A’s. I also remember pricing was not nice. I will dig through my search history today and if I find it, I will link it here. To answer your actual question, there is no way to make the later unit work with the 65 and back trans that I know of.
So I ended up buying a reproduction speedo cable an installing it with the proper gear and seals. I think it was around $150 plus shipping.(I know it is highway robbery compared to a regular cable) Needs to be pulled and lubed after six months of driving, but works well. Good luck, Doug.