Since you stated the '51 doors fit fine, it sounds like your problem is with the '50 doors and not the existing hinges or the latches. I would recommend trying to fit the '50 door in the door opening without the hinges or latches installed and place wood wedges 1/8" - 3/16" thickness all around the door, including the window opening to see if the '50 door actually fits. You can support the door with a floor jack while you fit it. If the door does not fit properly without the hinges/latches, it most certainly will not fit with them, without major metal working. Good luck!
