Finding a rim with 5.5" backspacing

The jegs knock off welds with 5.5" backspace said they were made specifically for fox body mustangs. They fit perfect on my valiant with a B body 8 3/4. I too had 4.25 bs rims and rubbed the fender.
http://www.forabodiesonly.com/mopar/showthread.php?t=320808