7 1/4 why weak?

this 65 cuda is original 273 2 bbl car, auto, with 7 1/4. so is it any stronger than a 7 1/4 say in a slant car or later car???? I am picking up some 8 1/4 and 1 8 3/4 out of a 65 b body, to have when needed. just wondering bout the 7 1/4.
small? mighty mouse was small!?? LOL