From what I've read, large bore ( AMG ) turbo M104 motors can't keep head gaskets together.

The OM crank is heavy and will need lightened. The absolute minimum is to notch the counter weights so they clear the piston squirters. ( you will need these too and have to modify the block )

These squirters have a valve that shuts them off at idle to keep the oil pressure frpm falling of too much.

There is a thread or two here on the entire project, you will need custom pistons or rods to make this work.