Duralast may be an Autozone brand, but they are still made by somebody else. Perhaps your bearing was mislabeled. I have sold auto parts for many years and have seen stranger things happen. With a vehicle that is 45+ years old, you never know what changes have been done to it.

thirty thou smaller is definitely not going to work. even an identical size of "x" [where id. and od. are the same] is a press fit, but not much of one. on the bearing in question, was it exchanged for another and the exchange measured ? in my 55+years of playing with this junk [instead of the smart thing, being playing with tiddlywinks] i have seen all kinds of mismarked, misboxed, misprinted parts catalogs and computer programs that anything is possible when it comes to ordering parts. with out comparing the parts you need with others, a blanket statement about sizing can not be accurately made. as has been said, bearings and seals are made by someone other than the retailer, and those parts are made to a universal sizing standard. you can even go to an industrial bearing place and get the bearing and seal you need, providing you have the [correct] numbers, as those places rely on the standardization of numbers being od., id., and thickness, as well as being a sealed or non sealed bearing, instead of the application, be it industrial, automotive, or other use.

Rock Auto shows the bearings for $7-18. Order one and be done.

Just my two cents, but for my vehicles I will only use Timken bearings.

Open the box and check before you buy it. The last Timken I bought turned out to be a generic bearing in a Timken box. There was no writing what so ever on the bearing. Could have been from anywhere. Would have been somewhat cheaper to just buy the junk chinese bearing instead of the same junk masquerading as a Timken.

Got one today from autozone that I had in the link & it was oversized, put it down on axel & its got room to move, loose on it, so I got to take it back, So I'm going to go with advance so I can get it next day!

https://shop.advanceautoparts.com/p/nati...rear#fragment-3

Done that once, Had a shop press it on & my rim was getting too hot even with brakes backed all the way off, after pulling axel out, the retainer ring looks a little side ways too me & I ask a guy at another shop in town, it looked a little sideways to him too, So I'm getting new one to go on again at a deff. shop, so I'll go with another brand at advance auto so I can get it next day!.. If the lowers priced NOS ones on e-bay had the retainer rig I may would of went with one of them!

All the Timkens I have used have Timken marked right on the bearing. If I run across one that doesn't it will not be used.