Trout,
We had a real good discussion about this a few months back. Many believe if you change the "Heads" on an engine, it is not a numbers matching car, and "technically" I believe the same way. However, I would consider it numbers matching as long as the number stamped in the engine block is the same as the "consecutive number" on the VIN. I also consider numbers matching to be MUCH more valuable than a car that doesn't. We may disagree on the price difference, but I believe we all agree on a numbers matching car being more valuable. In the end, it is what the buyer is willing to pay! But to answer your question, I would go to "google.com" and type in your question.