I've got a 1988 K30 4x4 Crewcab. I want to chop the wheelbase to 131". This will give me a 4dr with a 5ft shortbox. I would like to make the vehicle multi purpose like an Avalanche. Sometimes it can be a 4dr Suburban, othertimes with the removal of a top, it does pickup duty. If I physically attach the box to the cab, will the 1 ton frame flex, and in essence, make this a bad idea?