Same heads as the '96-'98 Cobra. There are quite a few swap parts to make them fit (Timing cover, pulleys, brackets, intake manifold, Alternator, etc). You might want to consider looking for a complete engine if you want to do a swap, to make sure you aren't missing any parts. Mark VIII engines can be had for a song. But if you get one and it runs well, you'll probably be better off just swapping the whole engine than tearing a perfectly good one down. You'd then at the very least get the aluminum block to go with the heads. The tough part will be finding a '96-'98 Cobra manifold to bolt up top.
You might also be further ahead just buying a set of Ported PI castings and call it a day.