The outlet of mine just measured at 75mm, inlet is larger still... though I didn't account for the taper out, so I guess 70mm should be more accurate for the area that actually matters. :blackeye:
But potential flow area is not the be-all end-all here. IMO, It's better to have a mathematically larger than "needed" TB, than to have a mathematically adequate one. Either way, you're still only going to be using whatever can get through your MAFS.
I have a Mustang 70mm TB on right now. The outlet of the TB is 70mm, but the inlet is actually smaller at like 67mm, IIRC. I have another Mustang 70mm TB that I bored out to 70mm straight through. As soon as I get a chance, I'm going to swap them out. When I do, I'll strap it to the dyno for comparison of before and after.