I have done a Zetec with Mk2 Escort auto box in my wee 100e. Was a doddle to do and the car runs and drives great. If you need to go automatic, as i did, then it is straight forward. I am using the escort box, torque converter, shifter and never yet had a problem. I originaly done my conversion using the 2.0L Silvertop, But changed it two weeks ago to an 1800 Blacktop.
My full conversion from 1600 Crossflow to Zetec automatic is on a different site, dont know if i'm allowed to say the site though.

You will need, Zetec engine, Mk2 Escort C3 auto box, torque converter and shifter, Zetec auto flywheel and auto tdc sensor, RS2000 propshaft fits perfectly as well. You will need a sierra 2.0L DOHC automatic starter motor. I used my cross flow starter with a 18mm spacer and it works great. You will need to get longer torque converter bolts and 3 spacers on each of the three bolts to go between the rear of the flywheel and the front of the torque converter. best thing i found, and still use, is 3 standard escort wheel nuts. PERFECT spacer size. You will need a vaccum outlet from the carb for the auto box as that changes your gears as and when they should. Then it's just the usual stuff for converting your car to take the Zetec engine.
E-Mail me for pics, parts needed and any more info you want.

johnaboyy@talktalk.net

Dont forget to put your conversion work and pics/details on here though
John.