Originally Posted by ChrisH

The head is different to a 2L Zetec, valves and ports are identical, first it has variable valve timing and the inlet cam is slightly different, the valve springs are different and 2.0L Zetecs have hydraulic lifters and ST170's are solid. It will bolt onto a Zetec block but you'd need to remove the variable valve timing etc but the ST170 head is better.