If your willing to make a little trip here is EXACTLY what you need.
http://67-72chevytrucks.com/vboard/s...threadid=90150
That's a rolling 71 4x4 lwb frame WITH a bed and axles in TX. Need,s cab and clip and he has some clip parts as well. If the 90 you have is 1/2 ton this probably has a better rear axle with a 12 bolt BUT the front axle is a D44 with small u-joints. You front axle is stronger.