Speedo Cable Help Please

The end you show there looks like the end that screws onto the back of the speedometer, not the trans. Does it have the same fitting on both ends? If so I'd say the company that made it screwed it up. I've rebuilt numerous 727's over the past 30 yrs. ranging from 1966 to 1990 models and they all had the same size connector.

Normally, I'd agree with you, but I ran into this exact same issue 5 years ago. And the part number he referenced above (CA-3014) rings a bell. I believe I found the part on Bouchillion Performance and since they're just generic app, I was able to give the part number to my local AZ and they had one in stock...and it fits...just about 8" or so too long. And the end that goes to the speedo is one of those quick release plastic doohickies.