Slant six

I know this is getting to be a common theme, but I am also looking for a slant six for my 73 Dart. The block is cracked I have nursed this along for over a year now but another crack has shown up and block sealer this time is not working. I believe it is rusting from the inside out. I think it sat for a number of years with water in the block. It is a shame because it runs great otherwise and I have not had any other issues with the engine. So if anyone has a /6 around,in Califorina or fairly close I'm in need.
Thanks Kevin