early a driveshaft conversion on ebay
That looks very similar to the driveshaft I had made for my '64 Cuda at Precision Bilt in Kansas City. They took a longer driveshaft I provided (from a Volare), cut it, welded on the proper end and the attachment...plate, for lack of a better word.
I no longer had to worry about a ball/trunnion joint. It was very nice!