It took a while, but eventually things get moving again. In terms of water pump, I had to go from a 3-hole (new) to a 4-hole (used) because of the Fiat 850's 100GL engine. I found someone who had two Fiat 133's for sale but he only wanted to sell everything in one go. Which he did, but not to me. After a long wait I managed to track down the new owner. And I could buy not one but two pumps. They were not very presentable but I needed them so who cares?

Fiat 850 waterpomp

A pump was placed on the block as a mock-up part so that I could build up the rest of the cooling system: an overhauled radiator and new (Teflon) hoses. The other pump was taken apart with a lot of brute force: the lid was stuck and rotted. Then I blasted many parts and purchased new parts. The neck of the large water hose had a few "transparent" spots so it had to be repaired. Has been done well by my regular machineshop (Broos in Breda) and again for a nice price. Thanks to Joop, one of the forum members, I was able to find the right bearings and last week the first pump was reassembled. The NOS-stock also included a new pulley and a new cover. After all, I want it to look as shiny as possible.

Fiat 850 waterpomp 
The seal turned out not to fit very well. Little tap with the hammer and .......
Fiat 850 waterpomp

I'll never do it like this again. After some extra grease and using another seal, the shaft went in by hand and the lid also slid into place. The parts information from Joop: SKF bearings 62202-2RS1 & 62302-2RS1 fit like a glove and together cost approximately € 56.00 ex VAT.