Thank you so much for all of the information on my axles.
Based on your replies ,
Since the axles dont have the white paint code inside the holes and as Royce stated the 8A is probably a date code,
It looks like my axles are most likely from 68 shelby 350/500 , 68 428CJ Mustang or 68 GT-E Cougar.
Also, that this certain style end casting were also used on 66-67 Fairlane 427 and 67 Shelby as well (at this length).
One thing I have noticed for whats its worth,
I have owned another set of these in the past and have pics of 2 other sets from a friend, and in all 4 sets when comparing their ends , one axle end is cast very clean/crisp with the hash marks visable ,and the end on the other axle, the casting is much more crude, and thats the side that usually has the numbers ,
or at least in the sets ive seen.