Brake Identification Help

Can anyone tell me what these came off of? We thought when we initially got all the parts that the previous owner was going to use these to convert the 1965 Barracuda to front discs, but after looking at them again, they look way to big. Seems to be stamped with "A 71312", but didn't see much of anything on the forum or the web about them. Any help would be greatly appreciated.

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