Throw some half-decent heads on there with a matching cam & intake, invest in the drivetrain, and it may be worth it. I know if I had a transmission that wasn't blown (the AOD is shot in mine) and a running 351W, you bet I'd be stuffing it into the Mustang!
My crystal ball just got back from the shop. That's how I knew you didn't have the original engine in that truck.
Hehehehe.