I apologize if this seems redundant, but I did a search and could not find the same situation mentioned. I have a 1979 Chevrolet Suburban with a 4" lift with rear blocks. I'm going to a 6" lift with rear springs. My driveshafts are fine with the 4" lift and my u-joints are good. Does anyone out there have the 6" setup on their older Suburban? Any problems with driveshafts being too short or angles too steep? U-joints? It is a Rough Country kit, and I don't know if the kit has an angled shim on the rear spring pack or not, or if it would be necessary to shim at all. Thanks for your time, and I apologize for the Noob question.