I have checked 7 different Ford housings plus several cut off ends laying around here and every one of them are 7/16---------
Please remember that not only do those bolts hold the axles in but the torque load from the rear brakes are exerting a shear load on those bolts
and the side loading from a turn/slide/etc are pulling on the axles against those bolts---------Please upgrade to the stock 7/16 size as a safety issue???