Walter,
Bugsy my '68 is running same size tires, stock rims, and lowered 1/2". I did replace springs and getting the proper springs from the usual sources can sometimes be a problem. Bugsy looked like an off road Spridget as I was shipped Rubber Bumper Springs instead. After 3 tries I ordered BE Springs and things were fine after that. Now my problem occurred 8 years ago. I've heard issue may still be going on. I'm not having any issues with tires rubbing at all.