Ford 9" in 1965 Barracuda...an option?

My 71 came with a Versailles rear, it fit perfectly. I replaced it because of the brakes, the odd offset on the axle, and the rotation on the housing ends. I've still got it, buy the 4.11 center section, get all the other parts for free. But I'm not shipping it so it'll probably still be here when I die.
I am aware of the brake issue and that it can be updated with newer Cobra Mustang parts, as well as the pinion offset of this rear axle. But, what are you referring to in regards to "the rotation on the housing ends"? Thanks.
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