I had the same problem with mine 3 years ago and I had heard that Calvert had a "bad batch" of springs I could clearly see the arch was completely gone and the springs went flat.I sold them and went back to SS springs and later found out that Calvert would have replaced them.I would call them and ask them what they can do about it.
Gus


64 Plymouth Savoy
493 Indy EZ's by Nick at Compu-Flow
5-Speed Richmond faceplate Liberty box
Dana 60