tire size

my 73 340 Duster had 245-60-14s on the factory rallyes out back and 215-70-14 up front when I got it and it bolted up and fit perfect on my 74 Dart Swinger and weren't too big for the rim and looked great
245-60 is not too big for a 5.5 inch wheel. It just gives it a little sidewall bulge
My father has 275-60-15 mounted on factory 15x6 rallyes on his charger with no problems in the 20 plus years they been on the car.
IMHO some sidewall bulge looks great