Then all bets are off.
You will need to measure all kinds of things.
Good custom tire shops have tools to mount on the hub to simulate verious back spacing tire size etc.
Look on the wheel near the valve stem
There might be some text stamped into the wheel
Photograph and report back
And by the way...
In the future lead with "I don't know if these steelies are stock or aftermarket."
Saves us all a lot of time.
