At least in the FWD Escorts, there is a ~7cm difference in the mk3 vs. mk4 engine mount heights (and also the mounting place in the body accordingly). The mk3 mounting location is lower than in the mk4. I think the same change also happened in the Fiestas.

edit:
Here is the difference. The picture is from my project album. Both mounts are modified for a Zetec/ZVH.