Factory BBP on 7.25 axle

A body 7-1/4 was big bolt pattern 73 and up only if it was a disc brake car.
All A body 8-1/4's were big bolt pattern.
F,M,J used 7-1/4 and 8-1/4, all large bolt pattern. More F bodies had 7-1/4's than 8-1/4's.
F rears are wider than A's.