[JL8Jeff]

My lift blocks have threads and the short centering bolt that came with them threads into the lift block and the bolt is what centers the block on the spring perch. Nothing threads into the spring perch. I would be scared to death to run 6" worth of lift blocks! Get some lift springs and shorter blocks for safety. Stacking lift blocks seems like a bad idea specially since they aren't physically connected. You would have 3 places that aren't connected that could lead to failure. Block to perch, block to block, spring to block.