Torque converter crack

That bushing looks a little discolored but I can't condemn it from what I see. Stick the new converter in there before you put the seal in and see if it's loose. "Register" is the size of the hole in the back of the crank that the converter snout fits into. There was a smaller one back in the early sixties along with a coarser spline input shaft, but they didn't all change both areas at the same time. Yours is a simple match up (68-78). Any converter from that era will work as long as the four bolt holes in the front of it match your flexplate (which you should be checking for cracks). I would look around for a used converter for like $30. If it's a 360 converter, just grind off the weights.