Another 8 3/4 question

I found one site that used 51.4" flange to flange . 52 5/8 was the most common # though.
I just dropped my axles off at the driveline shop today and would prefer to have the housing cut only once...lol....

Now I understand the whole big brakes vs A-body brakes . it's the width of the shoe that is the difference . right ....? That never occurred to me before .