Changing tie rod ends on my 73 currently have stands under the tc area right where the frame is the thickest. Is this safe to leave for a few days? Or should i put tires back on and lower back down. Car is in good shape just visions of sagging .

That depends on the condition of the frame.

Personally, I had my car on jack stands for months at a time with no apparent damage.

fine up front crushed in several spots under the pans from tards trying to jack in the middle.