1966 Chrysler 300 Rag Joint

1966 Chrysler 300: Can't get the 4 screws loose to remove the rag joint. Do two consist of nuts that will come off or are they welded on? They require an allen wrench, which makes it very difficult to work with. Are the brackets threaded? Can I cut the joint in half, cut the bolts off, drill out the broken bolts and use regular bolts. Thanks!
Author: RKC