Quindel54 makes a good point that I hadn't thought of. If the block and head are mismatched, the water passages could be partially blocked because of misalignment of the two. Don't know for sure if that's possible, but since you already need to pull the head, I would verify the part numbers on both the block and the head.
Sometimes shade tree mechanics do some strange things. Who knows what's gone on with that engine before Dogface got it?
