[PuzzleTruck]

Thanks DSRaven, for the extensive and detailed info. Yes, I'm the guy who will be figuring everything out. New spring perches were bolted to the frame so it rolls, and everything else was disassembled. That's why it's the PuzzleTruck. I'm using a power steering box (presumably from the same 73 Blazer) on an adapter outside of the frame and don't see any likelihood of interference with the tire on right turns with suspension compressed. I think the PO gave up when he was faced with the difficult task of locating the engine, trans and T-case without the body on, or any reference. I don't have a rear driveshaft, so I will have one made, or modified from a salvaged part. I used the front shaft as a reference because the length is likely to stay the same and has a double Cardan joint at the top. I lined up the slip joint grease seal with the wear marks from where it was originally, to keep the splines in the middle of their travel during suspension movement. I have rotatable bolt-on spring perches on the rear axle to dial in the pinion angle and will weld on permanent perches when the angle is matched to the drive train. Then I'll measure and cut the driveshaft accordingly.

What you're telling me about the drop in the Blazer mid-frame and needing to fab some drops for my cross member is what I was expecting, but wanted to hear it from someone else. Being the only mount, other than the two forward mounts on the engine, I certainly want to make it strong. I prefer to do as much myself as possible, but when I need heavy equipment to make it right, I check in with a friend who has a fab shop nearby. I'll probably cut the cross member to keep the middle section and make angled drops on the sides, with plates on the frame as you described. Enough typing - back to work!