Greg,
Our group has had this same issue for years. Firestone is the remaining US manufacturer. They are now down to running that tire once a year. You can frequently get offered 3yo goods as new. (The tire age is from molding date.)
The local junkyards may not be much help. They sure weren't in my case. You might try looking for wheels at
Southwest Wheel. This will at least get you their cross-catalog. While there collect all data. The hub diameter and offset are critical and not that easy to measure.
Good Hunting
Matt