Wow I am confused or it might just be that it is 3:45am
But lets see if I got this. You have a 72 blazer that you will use the frame from and convert it to 2wd. You then picked up a wrecked "truck" (blazer as well right or is it a truck?) and you will swap the body from that to the old blazer frame? Am I close or still sleepin? If it is a wrecked blazer than it was a 2wd to begin with or ? May be on my drive to work I will figure it out as I pass a few police stations while drinking gallons of coffie a few donuts and talking on the cell!
Kevin