1966 park lane ignition problem
 

have a 66 park lane, have been having ignition problems, sometimes would not turn starter off, finally just wouldn't start, brown wire from solenoid to firewall plug was melted, and also ground from coil to distributor was melted, ignition switch is new, solenoid is new, starter is good, battery is good, tried to start again with new wires and starter barely cranked, but also would not shut off, any help would be much appreciated, at the end of my knowledge on this one.....