What I'm told is that the 2.5 is the same as the early 2.3 (the lima motor). With that said I don't believe you can take a duratech head and just slap it on there. But there is a volvo head that, with some modification, can fit on quite nicely with some good results. From what I used to own (93 ford mustang 2.3l) the biggest application I have seen for it was on the mustangs with a turbo... or two lol.
pics of my Volvo head/2.3 Ford engine, almost done
this is one I followed for a while...... its completely done up. I'm in love with that motor. if you read a bit down the post I believe there is a guy you can contact that will help you out with such modifications.
And not to be a bubble buster, but if this is the only way to get a dohc on the 2.5, and you are not going to turbo or super it may not be to worth it. But I wish you luck in any case.