My 1/4 panels are spliting on both sides at the rear window line. I was told that it was from body flex because my 390 makes alot of torque. I've also been told that convertable GTA's had sub-frame conectors to tie the front and rear sub-frames together, so I'm looking into that. My question is how do I stop the exhisting cracks from growing? One suggestion was to drill a small hole at the end of the crack and then weld it up. Will that work?