I am afraid that most of the fusalage structure would have to be redone. Yes what you want to do can be done. But it would be a lot of work. If you want to try it. I would suggest you get a couple of copies of the plan made. then redesign as needed using one of the copies. use the other copy as your building copy. I hope you can fix this problem. Great Planes does or used to have a propjet of the phantom. Maybe you can find one. Also try RCM,MAN and the AMA site. They have some propjet plans. Maybe you can find one there. Good luck.

Mark Shuman