hey knud,
findig a good used waterboxer-engine here in germany is
like a fist prize in a lottery. some time ago, I called
some scrapyards around for some parts. "hello, im looking
for parts for the VW T3-Bus, I need....." - "we dont have
it."
There is a very big car breaker in Hamburg, called Thieso,
maybe you win, but dont be too hopeful.

Best wishes,
Michael