I have just pulled out my carpet and am getting ready to put in a cage. At the rear door area just inside there is a fairly thick stiffener plate that goes about 6 inches behind the door and appears to tie in with the rear lower control arm mounting. Under the factory sealer there is what looks like 4 large spot machine welds. My car is completely rust free in that area and the sealer looks original so I don't think it has ever been worked on in that area. On my car 7 of the 8 welds didn't actually contact the bottom pan. It looks like that piece was an important piece in controlling flex in these cars. Anyone else run across these welds incomplete like that?

 

one way to gain much stiffness is to weld all factory weldings again and not just a little spots like they do in the factory but 2 inches of welding, 2 inches not welded, 2 inches welding and so on. Hope you understand since I am not native english speaker