View source for Will Any 258 Fit In My Eagle?

No, not all 258's will not fit in your AMC Eagle.  

The engine has to be a 1980 or later one.  Make sure on any engine from a donor vehicle, other than an Eagle, the mounting bosses for the front axle are present.  Pre 1980 model engines will not have them.  Any engine after 1980 will have the bosses but you need to check to see if the holes were drilled and tapped -- if not you will need to have that done.  An interesting side note is that most all Chrysler 4.0 engines also have the mounting bosses even though they did not use them.

The Eagle oil pan is different too.  It must be from an Eagle.  Jeep and 2WD car ones will not work.

Other than that engines are still pretty easy to find.