[GWN7]

Do it yourself sandcasting is pretty easy. I've done it and there are a bunch of videos on YouTube about it.

The problem is whatever is the original is reproduced in the molding. You are missing a chunk of the flange and that would be reproduced and you don't want a missing piece of the new part.

Completely disassembly of the old part. Even removal of the brass bushing then scan the part. It should be a simple matter to remake the part on a CNC machine with the missing pieces remade from a stronger grade of material than the original.