Step 1 is locating a donor vehicle. My donor vehicle was a '92 Explorer 2WD, 4 door automatic. For your engine to function properly, you must consider a few things. Basically any 4.0 has the same bellhousing as the other ford V6's, and will bolt up to them, HOWEVER, if you are using an automatic, I highly recommend you take the transmission from your donor vehicle because the older automatics and the newer ones will run and drive together, but it's not very nice. This has to do with the different valve body solenoid setup mainly.