I think your tires should fit fine. However, you did not state if it was front or rear. I am pretty sure that I can get 275/50/16 on the rear of my 68 Mustang. I ran out of money before I could.
Up front I have 225/50/16. It looks like I could of gone with 245/50/16, all that I would have to do is probally roll the fender lip.
It is all in the backspacing of the rims. I think I have 4.5 inches of backspacing up front. I would suggest to get the wheels from a dealer that will let up play with it, and if you do not like them they would let you take them back. I hope this helps.
Ben