I think Magnum 3.9L is very doable, any issues would be the same as a 5.2 or 5.9 swap, except for the mounts if they are different (are they?). What I want to do is swap a 3.6L Pentastar and 8-speed trans; 292 HP and 30 MPG hwy in a big
ol' Chrysler 300, who knows what it could do in a little A-body.