I may be able to help.
I would think your best action would be to have someone in the states
pick up 2 used heads and have them reconditioned here, and shipped to
you.

I deal with salvage yards and machine shops all the time, if you want
i can lok into this for you. Drop me an e-mail at (remove DONTSPAM)
djdaveDONTSPAM@bigfoot.com

dave
master mechanic

The engine is actually made in Germany, although I don't know if the heads
are interchangeable with heads from vehicles sold in Europe (I suspect they
are). Why did you have the head "skimmed" in the first place? Given the way
the intake manifold and heads fit together on this engine to form the valve
cover sealing surface, that seems like a reciepe for disaster. We owned two
Rangers with that engine and they were very reliable and completely trouble
free.

Regards,

Ed White

Finding any good used heads will be your biggest problem. I could not find
one used set in
Texas that wasn't cracked. There is a company that makes new castings, but I
don't recall the name. The bottom line is, you won't find a used head that
isn't cracked. If you buy a rebuild, only buy from the Ford house. They have
them, but they have probably been welded. You might luck out on the heads if
the vehicle was mainly driven in cooler climates. Went through all of this
once; it wasn't fun.
Ron