2002 Ford Focus Question about Engine

I would recommend against using any other vin type engine because some engine configurations use Single Overhead Camshaft, some use Dual Overhead Camshaft. According to your "P" designation, you have a SOCH engine. Vin "3" uses a DOCH. Your single overhead design is not only mechanical variant dependant. There's a whole bunch of sensors and engine computer variants / configurations / differences which need to be taken to consideration. SOCH and DOCH are not compatible due to these many engineering differences.