2L Zetec ... unless you want to spend alot of money making something else work ...
Or the 2.5L duratec, but we all know its just cheaper to pick up a contour with a 2.5L engine in it already.
sure you can swap in a 2.5 but then you need a V6 trans, computer, subframe, engine bay wiring harness, etc ...
There was actually a post recently about someone who did this :shocked:. I'm having issues finding it, but it doesn't matter. It's a waste of money and time and effort anyways.