Separating ALH turbo

Any tips on separating the turbo from exhaust manifold on alh? Pretty rusty, especially behind where the actuator mounted. I scraped, I scribed the parting line, I sprayed and brushed. Hammered along the manifold casting. Put it in a vise and sprayed inside with penetrant, so far no luck.
Any trick I am missing? I would like to send it to be rebuilt or for a core exchange for a rebuilt. Thanks

Separating ALH turbo