Not quite an answer to your question, but this is one of the better deals I've seen recently for a 7.8 DME 3.2L engine.
https://www.ebay.com/itm/165811487468?
"This engine was disassembled for inspection, engine was found to be in good condition. It was reassembled with new head gaskets and new IMS bearing."
I've bought from that seller a few times and they do well.