If the hub bore in the wheel is like 73mm, then they're set up to use a 73mm hub ring to adapt the wheel to whatever bore you need. That's good news as hub rings are easy to get and cheap, whether you're fitting a Ford or Mopar.
The backspace could be an issue, but it might work in your favor. What is the BS on your wheels? I like the FR500's, too. They look like they'd be nice and light. Are these wheels pretty light, too?
Clair