Originally posted by mD5
well from my friends mx-6 the valve cover has a ford stamp on it. i could be wrong but i mean its a v6 ford motor. unless someone swapped out the valve cover 
Then the USDM MX6 has a Ford motor, but the JDM MX6 has a Mazda motor. I forget the engine code, but I looked it up and it's a popular swap with the MX6/Probe guys.