Hi Richard,
If it's any help, we just put a set of Coker American Classic White Walls in our 2002 Tbird, the size we got is: P235/55R/17 with a 1.75 inch wide whitewall. This size is slightly different than the stock tires, of P235/50ZR/17 that came off of the car, but we were told it would be fine, and they actually are, even think the ride is a bit better. I did extensive research on whitewalls before we bought them, including talking to Diamondback. Spoke to them twice, the first time they said that they could make the tires with a 2 inch wide whitewall, but when I called back to place the order, I was told they could no longer make them, not sure which info is accurate. Our preference was for a wider whitewall more like the 2 inch wide that Diamondback said they could do. We ended up going with the Cokers, even though the white wall width was 1.75 inches wide, but we're just as happy with them, paid $295 per tire, free shipping, no tax, however they were backordered at the time and we waited 5 weeks for them. There are also BF Goodrich Silvertowns with a 1.5 inch wide whitewall, these are available in P225/55R/17, I was told this is also an acceptable size for the car, these run about $20 less per tire than the Cokers. Hope this info is helpful, they look amazing and we're very happy with our purchase, feel free to look at the pictures of the car with the whitewalls on my profile.
Good luck!
Best,
Marianne