Hello all, I was looking on the forum and eBay for compatible engines for an '02 4x4 Limited Explorer (Vin: E), and I cannot seem to find a definitive indication of what is and isn't compatible. I want to minimize tinkering and messing with this and that. I saw on another thread that ANY long block will be compatible, even from a Mustang. But do the Mustangs and other Ford vehicle engines have the balance shaft as well? I saw Sport Trac engine pics and they show the intake placement, power steering and a few other things different, would it still work if I used the old intake? What about a Flex Fuel engine, would that be compatible with the existing harness and ECU? Is there somethings I should steer clear from in buying an engine that I would not be able to easily swap into my Explorer?