There is a bracket/holder than bolts into the block from the gearbox side, also there is 2 types of sensor as i found out doing my turbo conversion... An Xr2i or Xr3i CPS is longer than a fiesta turbo one, and the holder matches the sensor.

If the holder sticks out of the block around 25mm/1inch then you need the longer sensor, if the holder sits 5-10mm out then the shorter sensor in required IIRC...

Hope that helps!