Myself I just run Super Stock springs on my 63 and I have been very happy with them. I bought my SS springs around 2008 from Mancini as they are the ones rated at 3400 lbs. They have been on my car a good 10 years and have not sagged at all as the car still sits as it did when I put them on. I like them because the car drives nice and is not noisey and they work ok at the track. I do agree the Cal Tracs when tuned it will give you the best 60 ft but I don't think I would get more then about a tenth pick-up in my 60 if I changed to Cal Tracs so I just stay with the SS springs for now since they work fine for me. Ron