HI, Can you expand on what wires you have from the Zetec loom? If its a 1.4Carb it will need a EFI fuel tank with in tank pump, or an XR3i / RS Turbo MFI tank with pump, accumulator ect.
You will then need to wire in as per the normal RS turbo conversion to include a fuel injection relay, a fuel pump relay and an Ignition feed, Permanent feed and a couple of ground wires.
Not sure on the RPM output on the Silvertops but you may need to do something with the rev counter,
There is quite a bit to do.
Rich