Looking for an original A Body Dana LO23 or BO29 or Direct Connection

That is the reason for the special offset rear rims. Same offset rear rims on 8 3/4 and Dana rear. Listed in the Scheild book.

If they had Abody width rears, they would have used stock B-body rims off the shelf at much lesser cost and hassle.

Why wouldn't it use the same axles, bearings, gear carrier, and brakes from production vehicles?

Did the S/S Dana uses 10" drums? Wouldn't that have come on a disk brake Dana car? Just had a deep gear set.

An Abody big bolt 8 3/4 housing didn't exist. And they used B-body 8 3/4 off shelf with perches moved in.
Scheild's book is not all correct. Just look at the couch fan in the picture "after market one". I talked to him in person. Even he said he know some stuff is wrong. Just like he says they Used B Body front brakes. Not correct, they used A Body large bolt Kelsey Hays rotors on small bolt spindles. They also used those rotors on the 66 Dart road race cars. They also sold they over the counter. His book is still awesome with some good info.
The rear had 35 spines axles the factory car had the coast spine dana. They did not come out with the 35 spine axles until 1970 cars