Thats normal....you can improve it however. I changed my stock 3.23 gears for 4.11...now i dont have to mash the pedal to the floor to get her to get up and go.
I have a 2008 Sierra with the 4.8 vortec so i know what your going through!
---------- Post added at 09:52 PM ---------- Previous post was at 09:34 PM ----------
thats the 4.8 for you....I changed the stock gears in mine from 3.23 to 4.11 gears and that problem went away...more pick up off a dead stop and getting on the freeway I dont have to put the pedal through the floor.