Rear tire width max for 67 Barracuda

I just Bought a '67' Cuda Fastback and plan on putting Cragar S/S 15x7" 4 1/8" backspacing, +3mm offset with M/T ST 225/60 Radials on Front. Back will have: 15x8" Cragars w 4 1/4" backspacing, -6mm offset & 275/15 M/T ST Radials. Car has 5x4" Bolt Pattern, No Front or Rear Suspension Mods. Allof this Should Fit, Correct? Do I need to make any Changes. Thanks.