Why Tire Rub Now?

I had a problem like that. I put a brand new set of super stock springs on a 68 and within 3 years they had zero arch left in them. I replaced them with a new set of heavy duty springs and gained about a inch and three quarters of height. Then I took the SS springs to a spring shop had had the re arched and added a leaf and put them on another car and fixed it's tire rub problem.