Värmdö Motorteknik, Sweden might also help you out...not a long while ago they had acouple old EFI´s for sale complete and Swedes like to strip marine engines and put them into hotrods since early 60´s.
Kamala House LTD in Snetterton could also be a worthwhile call, and give Mark my regards.
Joern Amundsen from Norway has 2 complete ones for his Aeromarine III and he I think had some spare parts.
Usually you make the best finds in non marine related sources.
And I´m positive somewhere even in Europe there´s still complete 625´s laying around.
I happen to know a load of new K/E Class1 engines from the early 90´s.
Italians and French sure has parts also, just gotta find the contacts if you know someone who has raced something else on world class they have done also offshore racing back in the day for the fun of it.
Charlie McCarthy and Pat Weissman are worthwhile contacts in that aspect.