I have a 01 1500 sierra. I have installed a 6 inch CST lift kit with lift keys. I used the keys to lift the front just enough so that I am not rubbing the 35x12.50 SSRs I am running. I have lost a real reference point but I would guess that I am in the range of 6 3/4 to 7 1/2 inches of true lift over stock. (The CST kit gives a full 6 inches with their drop frame alone.) The rear is lifted by 5 1/2 inch blocks that were included in the CST kit. I am now going to get rid of these blocks and the factory blocks. I plan to use a combination of shackle flip brackets, longer shackles and custom springs. In the process, I would like to make sure the truck is level. The plan is to intall the brackets and shackles and then level the truck and measure for the custom springs. What is the proper way to do this? Should I measure to the bottom of the frame where it is parallel to the ground, right behind the front wheel and in front of the rear wheel, and make sure these are the same distance? This can't be as simple as putting a level on the bed rail can it?