I am changing or trying to change my body mounts on a 62 Impala. I found 2 near the back bumper, 2 just behind the rear fender well, 2 near the rear spring pockets and 2 on the firewall. All the bolts are out and I have tried jacking the body up to the point where the front wheel is starting to come off the ground but the body doesn't seem to want to separate from the frame. What am I missing?