I bought some pi heads from my friend today and when I pulled them out of the boxes I could tell they didn't come off the same motor. I was doing some reading in the stickies and found that they are both Windsors but one is the early Xl3E casting and the other is the 2L1E casting with 5.4L on it. My question is it OK to run these together or should I try to find a matching head? One also has a cam with a press on gear and the other has a bolt on, I haven't got the part numbers off of them yet. I bought them sight unseen along with a bullitt intake and throttle body for $60 so I figured I couldn't go wrong. Thanks for any input.