If it were mine, I would see about fitting a XF alloy head crossflow from the wreckers, and putting a turbo and stock BA intercooler or 2 on it.
The kits are reasonably priced, and will make more power, and turn more heads than almost any 289/302, at probably less money. That way it is different to nearly any other Mustang out there.
Either setting up a Holley for Blow thru, or putting it in a box, or fitting LPG to it and going straight gas would be your fuel options.
Around $6k would see it done, I think, if you could do the fitting yourself.