If they are longer than stock (which they are, I have them) they will give you lift. The only way they wouldn't lift the truck is if you moved the hanger forward and had a really crappy shackle angle. It may not be much, 1.5" IIRC so you may not notice it much, but they'll help when flexing as they let the axle droop/tuck more then a stock shackle would allow.
-andrew