don't forget to measure BOTH sides, no matter what you decide to go with.
the tolerances were so bad back then, that you could have up to 3/4-1" difference side to side, without the car in question being crashed in it's lifetime. 1/2-5/8" difference is very common.
that, and 50 plus years of potholes and other maladies, and who knows what a person will come up with that will effect tire/wheel fitment.