7 inch wheel tire size

This 76 volare has big openings so I can put some tire back there, not that a 76 318 needs much tire!!! It already has new 205-70-15 up front ( yep on 5 inch wheel) so trying to stay about level. So a 245-60-15 would be bout that.
I have always ben told, a car needs to ride bout level on the highway, although Mother Mopar had the 70 TA-AAR which came with If I remember right G 15 in back and what E 15 up front, 2 tire size different. I had a few back in late 80's and they handed fine ( for an E body! ) It needed that rake for the side exh. tips no doubt.