Just guessing here, but it looks like the surfaces are too course for a steel gasket. I know they all say to use nothing on the gaskets, but even with a near mirror finish, I use RVT around all water passages, block side, and head side. Not a ton, just thinly wiped with my finger around them all. Some of those lines I see on the picture, look like they would channel water to the outside of the block.

Another very outside chance is check the depth of your dowel pin hole in the head against the height of it in the block to make sure it's not resting on the dowel. Set the bare head on the block and make sure it doesn't hold the head up.