[watahyahknow]

youre going to need the transferbox too , dont know if it will fit on the gearbox/automatic you have now and the driveaxles (are they the propper length)
i think the best thing to do is make a regtangle using the wheels as corners and measure height and x y axis on the driveaxles diffpumpkins and trasfercase and use drainpipe and some pieces of styrofoam or sumting bend out of weldingwire to a simulair size of the parts you want to build over to place those parts somewat under the chevy sitting inside the same square on the ground

it should give you some 3 dimensional idea of wat needs to move out of the way , raizing the truck at the springs would help it moves the front diff away from the oilpan ............ i actually seen people weld a complete 4x4 chassis under the stripped 2wd chassis with square tube plugs and plates slapped on the sides to fill the gaps
you can put the chevy tranny and transferbox in the lower chassis wish would put less stress on the knuclejoints but give less groundclearance between oilpan and ground the steering definetely on the bottom chassis ... no bumpsteer , no problems as long as you can connect to the steeringwheel , i doubt that would be legal but if done right its verry strong