Bolt-in frame stiffener enough?

[LS short box]

On my 68 I added some bracing to the frame. I made my own parts. I have a pic of the rear frame section. What you can't see is the tubing that I added from the the trailing arm to the trans cross member. One on each side of the drive shaft.
I got the idea from an article in Hot Rod magazine where they featured a 68? C10 that was modded to run on the road course. Truck was read. I do not recall year or the month of the feature.