I have 245/50/15 with 15x8 and 4.5 backspacing on my 68 Notchback. It's a little close on the inside, but I have never rubbed. I have an 8.75 rear end with stock small bolt pattern axles that have been redrilled to larger pattern. If you have aftermarket axles, they have a thicker flange and the rim will be pushed out an additional 1/4" or so.
That taller tire/rim combo will still fit fine.
The outside dimensions and position will dictate the clearance. When you figure out the height, width and in/out position (backspace/offset) you will be able to compare the fitment of a 245/50/16 someone running a 245/60/14 on a 14x7 rim with 4.25 backspacing. Both those situation have the same outside dimensions and positions.