Hi Dan,
I have an engine for sale that is completely machined and all new parts for sale but Buyer would need to assemble engine. I'm selling it for $4000. My Mechanic will put it together ready to drop in for an additional $2000. So, I would say for a completely rebuilt engine ready to drop in a halftrack would sell for $6000 or so. It all depends on parts and labor costs though. Also, I sell new made, complete engine overhaul gasket sets for these engines.
Steve A.