Probably quite a few if the contour is '98 or later, or the zetec "E" type. Earlier contour fours will have many more differences, since motor went through quite a few engineeering changes. I have one of both (98 tour and 00 focus) and it appears some of the parts would swap. I know the coils have different attachment for plug wires, meaning coil and wires both must switch. I did it once testing for a problem. If you use too early a water pump the scroll will be backwards, easy to overlook but motor will overheat if wrong pump used. A lot of vacuum connections on intakes are in different places also, intakes and throttle bodies subtly different. The automatic trans (CD4E & 4F27E) on both are totally different, don't know about block bell housing bolt patterns or machining at crank end for torque converter. Timing and serpentine belts are the same as are belt tensioners. All timing pulleys (except VCT exhaust?) the same too. Exhaust manifolds different. Some coolant hoses changed attachment points but basic system the same. Starter same. Alternator slightly different because one has the PCM controlled variable charging. '98 VCT head will be different from '00 non VCT head.
