Ok, here's the story. I rebuilt a 62 409 for my 62 Bel Air. The car originally came with factory A/C. I decided to go with a hydraulic cam. The lifters I installed are Delphi brand, and are floating at higher RPM. There is less than 75 miles on them. The question is can I replace the lifters, without replacing the cam. I have heard this is a bad idea. I remember doing this in the past with no problems. Changing the cam with the engine in the car creates a problem with re-sealing the oil pan without having it leak.