Overdrive transmission

What is the abhorrence to reinforcing the floor ABOVE the crossmember? It takes a very proficient welder to do all that overhead welding, but if the section in the tunnel was sliced completely out, a lot could be done from above. A few layers of strap up top would go a long way to strengthening that area. I've seen plenty of these that had very few factory welds attaching the reinforcement to the floor up inside the tunnel anyway. I hate it when sparks go down my neck! Bad enough to fight them when cutting the reinforcement out from below, but at least that's only two vertical cuts. And why not just build an entirely new LONGER crossmember; drilling extra holes in the reinforcement? The earlier pre-67 a-bodies needed cutting for dual exhaust anyway.