hi, and welcome to the den. $650. is a very good price, especially if the car is not rusted out. If all it needs is a carb rebuild, may I suggest you try that first, a carb kit is only $30. or so, and your 80 should have a non-feedback Carter BBD., get it running, and see what else it needs, before you jump into an engine swap. The most common, imo the ONLY cost effective engine swap into an Eagle is the AMC/Jeep 4.0, do some searches on that, lots out there. Even here, go to "Your Eagle(s)" section, and check out the thread "Tootie is Alive...finally" to see a well done Eagle. The Ford modular motor is physically very large and wide, and probably won't fit, and you will have to reengineer the whole car. good luck, gz