I did a shackle flip on the rear of my K20 and now the pinion points up too far. I have some small steel shims (I hate shims, but it's better than new sping pads!) that I can install with the thick side towards the front of the truck that will bring the pinion down some, but I don't know where to put them. I have 5.5" lifted rear springs and a 1" zero rate on a 14 bolt. I want to put the shims between the spring and block, but in the pic you can see that since the spring is curved it doesn't sit flat on the block and I'm afraid that the block will rock a bit and crack the shim. Is it ok to put the shim between the spring and axle perch?