Speedometer Cable help

I just got back from the parts store with a speedo cable. I pull the old one and compare the ends. The transmission end has larger threads on my old cable than the new end on the new cable. Otherwise everything is the same.

The car is a 904 -318 - 7 1/4" in a 1973 Duster.

Does anyone have any part numbers for the correct speedo cable for this car?

Thanks, ROB