So if am adding a lift in the front that's going to give me 3" of total lift in the front, and I'm building longer shackles in the rear, how much taller do I have to make the shackles to equal the 3" in the front? I've been told I will gain a half in for every in added, is that true?

 

Unless this is an offroad beater, dont use lift shackles. Use lift leaf packs