Uh Oh, what happened? Check with your reputable local salvage yard. Good ones will give you a warranty of some sort that you won't get from a craigslist type of deal. These drivetrains aren't too hard to find
I'd hit the salvage yards for an explorer 5.0 they cost the same and come with the GT40 style heads and intake.
Car-Part.com--Used Auto Parts Market I've found 60k mile GT40 engines complete for as little as $300.