Still shaking down my new purchase. Runs like a mother f&$@“r. But I’m trying to figure out what is going on in motor without pulling stuff apart. It has the gt40 intake but I don’t know about the heads. Sounds like a damn monster. Can definetly hear a nice cam but my I want to know about the heads. Other mustang enthusiasts want to know what it has because of the sound. Bought it from a dealer and they don’t know how to change oil let alone tell me about the motor. Is there a way to tell what heads are on your fox? I’ve looked for the typical aftermarket markings on the front the them but there is nothing there. They look aluminum. Are GT40’s aluminum or iron? Trying to tap into everyone’s expertise before I pull this thing apart. Only because I want to know