Originally Posted by Nickshu

You can easily run 245 fronts and 305 rears. 315 rears will fit too but they look a little pinched on 11" rims. I have run 225,235,245 fronts and 295,305,315 rears with no issues

This assumes that the aftermarket wheels you have are in stock narrow body offsets of ET53 front and ET63 rear.