I measured the spring perches on my 90 K5 last night and it measures approximately 42.5" center to center. I measured three M1008 military 1 1/4 ton trucks (essentially these are 1984 single wheel Chevy one ton 4x4s) we use as grass rigs on the fire department and they all measure approximately 40" center to center. I am getting my K30 donor this weekend, so I can't get the measurements off of it yet. Three questions: Does anyone know the measurements of a K30 single wheel one ton? Does anyone know the measurements of the dually spring perches? Has anyone moved these spring perches? Also, I could move or replace the front spring hangers with one tons that I can get from the factory that will move the springs closer to the frame and get the shackle flip kit from http://Off Road Design for a one ton, that will move the rear closer to the frame. But will articulation be compromised since the springs are closer to the frame?