On a zetec blacktop do I need to use the standard temperature sensor in the head or can I use a different one? If so where is the best place to put it?

Cheers
Mike

Depends what you want it for...

Standard one tells the ecu what the temp is, doesnt work with a gauge..

Early engines had two sensors, in the thermo housing, one for the ecu (on top) and one underneath with an 1/8th NPT thread for the gauge.

Is yours the late one with the sensor in the head under the inlet manifold?

Yes, sensor under inlet manifold. Only need it for the gauge. The gauge came with a sensor so it seems logical to use that one if possible.