Magnum 500 and Disk Brake Question

I have just installed a 73 single piston disk brake system on my 67 Dart Convertible. When I bolt my Mopar Magnum 500 style 14 inch Rims to the rotors I have an interference problem. I think they are contacting the outer bearing boss on the rotors where the spindle is. Any ideas for a fix? Different style Magnum? Version of wheels? Anyone else have this issue?