I am completly confused when it comes to wheels, with the whole back spacing, bolt pattern and what not. I have a 67 Dart which has upgraded disks up front and a stock small bolt pattern rear end. I currently have SS cragers up front which are 15x7. I want to get matching rims in the back but am lost on what is the correct bolt pattern, back spacing and any other variable I may not know. I bought an adapter which goes over the small bolt pattern in the back and allows the use of the bigger bolt pattern wheels to mount. My question is what are the specs I should look for when deciding on the backspace and bolt pattern?