if you remove the injection system to try run it on ford zetec ecu it will think something is heavily wrong and advance the spark slightly so will run shit or eventually kill your engine from pinking
If you want to run carbs on a zetec the best option for you is to get the esc (electronic spark controller) loom and red block found on single point injection escorts and mk3 fiesta, this is designed to run just a spark and what all the boys with mk2 zetec on carbs use! Then you can use your original flywheel with no problems.
Just encase you do need one i have the complete spark loom and esc panel with map sensor built in to run spark!
some of the details of this can be found in link below
"Carburettors
There are a number of propriety manifolds and kits available from your local Ford tuner to drop a pair of Italy's finest petrol pumps on. With the fuel sorted, how do get round the sparks side? The Zetec doesn't have a distributor, just a single crank sensor using the 36-1 tooth method of encoding (36 teeth spread around the back of the flywheel, but with one missing at the datum point), and a crank sensor (only used for sequential injection). You can either go to an ECU supplier to provide a ignition only ECU for a few hundred quid to use the existing pickup and coil pack, or to get 95% there, you can use the igntion system from a late CVH Mk4 Carburettored 1.6 Escort. This is a complete standalone ignition system with a sufficient ignition map to run the engine quite well using the ESC system, and uses the standard Zetec pickup and coil pack. Pick up sufficient wiring from the donor car, and you'll be left with 3 wires; 12V, ground and a feed to the tacho!"
it looks like this:

in the link below you will find a guide on how to fit it! literally plug and play to all sensors! you only need to match up three wires, ignition live, ground & tacho for your gauge
hope it all helps
