I have done a search for what componants to use to fit my box to a 20 zetec and most seem to use a plate from a sierra 18 cvh which is 215mm and an 18 zetec cover which is 220mm

my zetec is running 240 mm disc
is there a reason for not using the mondeo clutch cover and plate as the splines are both 25.4 x 23
hope this makes sence
whats the betting iv missed the obviouse

I think the answer is, most changed from 2.0 flywheel (Very heavy) to 1.8 flywheel
and the 2.0 clutch doesn't fit the 1.8 flywheel.

so if they use the 18 zetec flywheel why dont they use the 18 zetec plate that goes with the flywheel

Have a look here mate.

I asked a similar question. Best bet is to get a 1.8 zetec flywheel and use a 1.8 zetec clutch,.