1965 DART GT 273 4BBL

I remember someone saying awhile back that after awhile the factory began replacing 7 1/4 rears with 8 3/4 rears due to all the breakage on 4 speed cars-....may be a technical service bulletin floating around out there...
I think the 5-50 warranty covered 7.25 rears that broke and replaced them with 8.75 in manual trans only. Rumor mill talk, but makes sense.