steering gear box

I know that 1969 used 1/2" mounting bolts. I fought one bolt all the way in my 1969 Dart slant w/ p.s. I finally found the factory had installed a 7/16" bolt where 1/2" should have been (they do look very similar). I guess the worker just turned the dial up on the impact wrench to get it in as the line rolled, and probably had a whole bin of wrong bolts. Have installed gearboxes in both my 64 & 65, but didn't notice the bolt size other than they went in easy.