What size tire for back of 69 Dart GT vert?

Brought car to tire shop and he suggested going with 235 60x14 all way around which would enable me to rotate and move around as needed.

I was originally thinking about going with the "old school look"- bigger beefy in back/smaller in front... but not opposed to this suggested option.

My back tires just look too small.

Dart down road.jpg