Big Tom,
If you are talking about the metal rocker supports that tie the front bird cage to the rear section they are spot welded everywhere. The front of the cage has an outside brace that is welded and the under side is spot welded to the body mount plate in the front. I have taken them out and not much fun puting them back, it is not a job for the novice.
If you lift the body completely off the bird cage, check some of the older vette mags they tell you how to do this, then you can access the entire channel with ease. Still a real pain to put in. I have a pair that I removed from a wrecked '81, unlesss you get the entire body separated from the cage there are spot welds that you can not access.
Bottom line it's a lot of work.
tcxd40