83 thunderbird motor tranny question
Reply #2 –
Driveshaft is Tbird/Cougar specific.
As for the rest of your question...I have the entire powertrain from an '89 Stang GT in my Sport. Of course, if your car was 5.0 to begin with, everything is much easier, but even if you've got the 3.8, all you'll need is wiring, mounts (your year car can use the Stang mounts) and you'll of course need the 5.0 EEC.
The fuel lines may be different too, can't say for sure as I've only ever owned '88 year 'Birds.