Custom Rallye rims
You can contact Kelvin's Tire at 306-955-5552 in Saskatoon, Saskatchewan. They will remove the center from any wheel and weld it back together, on a jig, with whatever backspace you want. They may even have the wheels you want. These are the guys that made a 7 X 15 Cragar SS out of a 6 x 14 for me.