Hello,

I know at Burton Power is selling new heads (not COSCAST) in the UK.
See https://www.burtonpower.com/motorspo...b-sc1207a.html
I notice at this head is using 36.24mm inlet valves and 32mm exhaust valves, so you should find out can you use original valves in this head.

Original 4wd valves are IN 35mm and EX 31mm.

Nowadays it`s really difficult to find good used head. Usually used heads are skimmed already to minimum thickness. Going by the ford manual its 138.68mm. You can use heads after minimum thickness, but then you will need to use thicker head gaskets.