Good you've now identified year and model, unfortunately you've got one of the problems I warned about.
Both mine are electric speedos so I've no firsthand experience with mech ones on Contours. However, if you can't get access from under dash then you'll have to disconnect cable in the engine compartment. It's 2 separate cables joined just before firewall. Again, with all the air hoses, etc., not easily accessible. Once you separate at joint then you should be able to push and/or pull (gently)from dash side, to get enough of the cable into the cabin to give you clearance to work. Pay attention to cable's firewall grommet and ensure it's ok on completion.
Good luck.
