72 frame twist issue

[72bigred]

396 700r4 swap into my 72. Am I crazy to believe that the transfer case and engine cross member give this frame all its rigidity? Just mocking things up with the members loose and I get over a 1" drop from my right frame rail. I took the engine weight off and the frame perked up, tightened the engine cross member and now only 1/2" drop. Leads me to believe I need to take the weight off the tranny member and tighten her up and then tighten up the engine member before putting any engine or tranny weight on it at all.

Any insight would be great, I have been playing with this mock up for a couple of days, starting to go a lil nuts over thinking things..