Rolf, the 67-72 Eaton is an HO52 rear axle, itt just that some of them during those years had a 4.10 ring and pinion instead of the 4.57 most were equiped with.
The housing, cover, center sections will all look the same for all the years. All of the Eatons were HO52's.
DG


Denny G
Sandwich, IL