[Grim Reaper]

The main differences between a 4wd and a 2wd is what crossmembers and spring mounts that were installed on the 73 up. I would think it was close to the same on the 69-72. Now a real 2wd blazer would have had the coil rear suspension is my understanding. That should still be a crossmember issue. If you don't mind leaf sprung rear then no biggie. Next issue is the rear spring mounts on the 73 up they were shorter then the 4x4. You MIGHT be able to use the spring hangers from a 73 up 2wd to get the rear down. Problem is the frame shape is different on those years. I would think the best doaner would be a short bed truck or a 2wd 73-77 blazer(frame change in 78 and they stopped making 2wd blazers in 82) if you can find one.

Front. Cut out the 4x4 cross member and the 2wd suspension should be a bolt on. roblem is your proably need to pull the engine for this. Your proably going to need to change to the clam shell motor mounts as well.

The front suspension from 73-87 truck will fit but you will need to drill a couple holes. I was about to do this swap on the 70 Burb I had to get disc front and 5lug. I had a 77 doaner front suspension (was actually out of a 2wd Blazer). I had been told it would work and I measured everything and it sure looked like it was going to work. The 73 up has a couple extra holes but the main holes that were important were in the same place as the 70.