Why not just cross flow the cooling on the head? Three inlets on the passenger side, each between two cylinders, and three outlets on the drivers' side between the same two cylinders. Run a dry deck, electric pump, and split the pump output between the head and the block.
Or, maybe just increase cooling system pressure like I did. 28 to 30 psi solves most nucleate boiling problems. Or better yet, go with a non-water based cooling system.