I used new SS springs in 2006 on my 68 b body when I first put on MT drag radials. After a few launches on the street, They permanently bent the front segnent of the leafs. Such severe spring wrap up. I kept throwing pinion snubber bumpers off the car with them. They were complete garbage! I took ‘em out that week and put in Caltracs. 16 years on Caltracs and no sag at all and hook very consistently. They do offer +1” height, which I got on mine.