The 88 is fuel injected. The 67 is not. To get a fuel injected engine to work in a non fuel injected vehicle is a lot of work, and will cost you a lot of money. If you have the entire 1988 Mustang at your disposal, it will be easier, since that is where the majority of the parts will come from. It would be easier to fix up the '88.
Take care,
~Chris