I would say the hinges are out of adjustment if you have to push the back corners down. It is certainly that way on the 62-65 cars. Don't know if that newer B body is much different, but I doubt it.

If it is an adjustment, boy, can that be "fun". And moving the hinge in the right direction is really a guessing game.

If your car was an early car as mentioned, I would raise the rear, and lower the front of the hinge to fix that. That doesn't seem right, but it is. Best of luck to you.