I've done 1.6 ZS conversion before, 1.7 shouldn't be very different except for the inlet manifold size. The only* room problem will occur where the inlet manifold meets the front panel where your chassis number plate is located. You'll have to cut some of it to make room for the manifold. Other than that, you'll need a Fiesta Mk4-5 or Puma bell housing to get the starter motor to the other side. And a custom engine mount might be neecessary as Ka has a different mount style compared to Fiesta and Puma. The conversion will compliment F/R balance too, as ZetecS engine is a lot lighter than the old ironclad.