steering box bolts

I am fabing some bumper brackets and would like to know what size and lenght of bolts are used to hold the steering box to the uniframe. I would just pull the bolts but will not be able to get to work on this until all of the stores will be closed for the night. any help is appreciated.

thanks

7/16x4-14 is stock
I used 4.5" long bolts when I did my brackets, to make sure I got full engagement even with the 1/4" sandwiched in there.