3.0 ford ranger, 3.0 ford taurus, 3.8 front wheel drive (ford freestyle) the 3.8/4.2 in the mustang or f150 (rear wheel drive) will not work because they use the 5.0 transmission bolt pattern. it has also been ruled that the 3.8 swap isnt worth the time/headache and finding a donor vehicle is a pain. just find another 3.0 out of another ranger or a taurus (intake and exhaust manis are backwards on the taurus but the lower plenum to the oil pan are identical) and swap it in. the reason you cant use any other engine is because the transmission will not bolt up to any other motor and the bellhousings are not interchangeable on the m50d. if you wish to use a dif motor (2.3/2.5/2.9/4.0) you will have to change the transmission and the engine wiring harness/computer/fuel system. hope this helps you.