Yeah, as Luke says, I don't really know much about the Zetec S 1.6 engine.

I'd just get a 2.0 Focus lump as Luke suggested and bolt that in with a T25 or T3, and some management, possibly Megasquirt for a budget project car. Pistons for the Focus Zetec engine are very cheap, £500 will get you 8.2:1 pistons with rings, H section steel rods inc ARP rodbolts. Pick a 2.0 engine up for next to nothing these days aswell.....daft not to