Okay after draining my brain on what to do I have decided to keep the factory look of steelies with dog dish caps on 62 Polara. It currently has 14" steelies. I want to beef them up to 15". Summit has black steelies at 15x8 for rears with backspacing of 4.5" and for the fronts 15x7 with BS of 4.0". Question: Will these work? Backspacing on front? I am guessing my existing dog dish caps won't work on 15" wheels. See picture. Question: Where can I get dog dish caps to fit 15"? New or quality used that will fit. Don't know if I would be good at modifying to make things work unless it's a no brainer. Also, as per other members here the following tires should fit. 275/60/15 back and 225/70/15 front. Please confirm. I spend way to much thinking about this stuff. But it is kind of fun digging in.