you will need a early model AOD that is not controlled by the ECU. I know a 1988 model was cable controlled.
You can buy a kickdown control kit from Lokar Performance. It MUST be adjusted correctly or you will burn up the trannie, quickly!
Lokar Performance Products: 1-877-469-7440
I think the AOD is a much better trannie than the C-4 and C-6 in a street Cobra.