big bolt pattern for 7-1/4 rear??

Just took a look at what I had. Found a 8 1/4 out of a 89 dip cop car (non SG).
also a 8 1/4 non SG in my wifes' 88 Dippy
Several early type 7 1/4's both small and large BP
One late style 7 1/4 (assuming "C" clip).
What I did notice, on the late 7 1/4 the axle tubes are the large diameter, and "neck" down in size, where entering the center section. This is different then the early BBP 7 1/4, that has the small tube, that gets larger at the outer end of the tube. Also the late 7 1/4 has only four brake backing plate mounting bolts, where the early BBP 7 1/4 has five.
Learning a lot, here.