You can get away with only having to remove a small amount around the top of the port where the injector cutout is. But the manifold needs to be altered.

As the ST170 manifold fits to the zetec head, this is how it lines up



This is the ST170 inlet on the zetec head, but the steel inserts in the maifold need to be removed so it can be lowered on the head.



The scribe line is the difference in the two parts