Still leaking?!!!!!!

[Gs835.8Stang]

My only thoughts are (and you have probably already thought of these or tried these), are you sure the block/heads are not cracked? It seems like perhaps the heads were not cast correctly. As long as you are sure the deck on the block is square (and was done properly, I have seen blocks that were not properly decked cause numerous problems, when I refer to being done properly, I not only mean a square surface, but also in keeping the correct angle with the line bore of the block), the only other obvious thing I can offer is are you putting any sealant on the head bolts that go into the water jackets? That will case an immediate leak for sure. I believe there are a few on the Windsors that do go into a water jacket. I hope this helps. Good luck, let me know what the problem is/was when you get it figured out.