The standard "enhanced stock" mopar muscle car look with the 15" magnums is front 15"x7", with 4.25" backspacing 235 60 15 tires

rear 15"x8", with 4.5" backspacing, 275 60 15 tires.
this gives you a 2" taller than stock tire in the rear, but a "beefy" looking tire.

68 Charger, 383 HP console auto, spring green, stock restoration