When I shortened my frame, I welded the cuts back together, and then scabbed 1/2" steel plates to the inside and outside of the frame. The plates were bolted together with (8)-1/2" grade 8 bolts. I chose not to weld the plates.

My feelings are that the frame will definitely flex and where you interfere with this flex (by stiffening) is where a stress crack will likely begin. It makes sense to me, maybe not to a metallurgist. I also believe this contributes to ‘some’ of the front clip problems that are showing up.

I also figured that, once this issue is finally resolved and I am wrong, I can always weld in the plates.