you might as well do a whole timing belt and water pump change while the head is off as you have to remove the timing belt anyway and the water pump is easier to get to with the head off...might as well have the cooling system flushed and pressure tested when you get the new head installed

if you want more power
- get the used head port & polished with a 5 angle valve job as
- get the intake manifold and tb p&o too
- get a hondata phenolic intake manifold and tb gaskets to decrease temp
- change to a cooler themostat (runs the fan longer allowing the engine to run cooler = more power