7 1/4 as bad as they say
7 1/4s are actually pretty strong if the rear gear is a 3.23 or numerically higher (3.55,3.73,3.91,etc.). The only ones I have managed to break were in the 2.76-2.96 range and they usually split the carrier. Add a Suregrip and the strength improves dramatically. I am currently running a 3.55 7 1/4" in my '66 Valiant with no problems so far.