I have a 1984 GMC K20 4X4 Suburban and i am putting in a 2003 H.O. Cummins. I know the weight difference is about 400lbs more than the 6.2L diesel that resides in the engine bay. So my question is if i went with a 6 in heavy duty lift kit for my Suburban would that be enough for the cummins or would i have to put a bigger lift up front  such as a 8 in lift. Thanks for any help and advice you give.