wish you could see me trying to tilt my head far enough to one side to figure out what that 2nd picture is of
in a few more hours you'll probably get input from some of the more knowlegable members but I think the front crossmember is a pretty stout piece and not likely to have tweaked. and if the tires weren't hit the control arms etc are going to be fine
it's not just disc brakes, it's POWER disc brakes, AND power steering--IMO, 2 of the 3 best mods you can make to the '66.