Although everyone refers to it in regards to sway bar stiffness ( vertical as you say ) the steering box and linkage DO put a lot side to side bending force into the left rail.
Although unit body with bolt in crossmember , my mothers 85 Camaro popped welds and cracked the rail from steering input.
After repairing, I put in the "export brace" as it was called to tie the rails together.
As you say , for a brace to measurably help the frame rails deal with sway bar inputs it would have to be pretty tall.
Or weld in an upper and lower with a triangulation diagonal.
If you can't find triangulation in something, it ain't doin much.
You need to look at something and picture the lines of force ,so to speak.
My brace, its main puroose is the relocate the shorter arm sway bar back for link alignment and to some extent helping with side to side.
I also seam welded the front rails when the new frame went in .
Although unit body with bolt in crossmember , my mothers 85 Camaro popped welds and cracked the rail from steering input.
After repairing, I put in the "export brace" as it was called to tie the rails together.
As you say , for a brace to measurably help the frame rails deal with sway bar inputs it would have to be pretty tall.
Or weld in an upper and lower with a triangulation diagonal.
If you can't find triangulation in something, it ain't doin much.
You need to look at something and picture the lines of force ,so to speak.
My brace, its main puroose is the relocate the shorter arm sway bar back for link alignment and to some extent helping with side to side.
I also seam welded the front rails when the new frame went in .
