Hello Tim,
I've have the same problem as you. I have a 3837004 block which is cracked at the water channel. I gave the block to a motor services, that should look if they can weld it.
If not I have another block 3835911 which I planed to restore it with the complet turning parts of the 3837004. I will measure it and I hope I can use all turning parts with out the water pump.
pictures of the two blocks, you find here:
http://www.kripahle-online.de/unterricht/?page_id=2408
Wolfgang

I'm working on a Chevy Pickup 3600, build 1953 with an 235 cui engine.
Here you can watch my truck: https://www.kripahle-online.de/unterricht/?page_id=2532