Charger battery.When I tried to hook up my battery the engin tries to start and key is off. Lots of sparks at the terminals too.???
More than likely a faulty starter solenoid; the contacts are burnt stuck together.
Another possibility could be if the starter solenoid wire is being powered up while the key is in the OFF position; faulty ignition switch or modified wiring.
This is easily checked; simply disconnect the small wire at the solenoid and see if the vehicle still tries to crank when the battery is connected.
If it does the starter solenoid is at fault and if it does not then the ignition switch or wiring is at fault.
Be certain that you are hooking up the battery correctly. If this car has not been modified, I believe it is a 6 volt system with the positive terminal grounded. Ford and Chrysler products through 1955 were 6 volt positive ground.