Suggestions/help for my 440 build/swap

If you have motortrend on demand, lucky and tony do an 8.8 explorer swap into a 73/74 Dart or Duster. They of course make it look easy, but it does not look as scary as others. An 8.8 from a 5.0 Fox would be close width wise and is already centered unlike the explorer, and would be plenty strong. The Mustang one you could buy 31 spline axles and a 31 spline limited slip which are actually quite cheap relatively speaking.