/6 cost

66aCUDA said
To Address your current problems. I dont think your mechanic was worth his salt. I would suspect your "head gasket leaking oil" is most likely the spark plug tube seals are bad. We can most likely talk you through diagnosing your problems and repairing them your self.
If you are bent on having the engine replaced expect a good shop to charge between 3 and 5 K for a good warranted rebuild or "new"Rebuilt engine.
Frank

X2 - I might buy into the thinking that it would cost as much to replace the engine if it were a newer vehicle, but it's stalling which is likely a carb issue. I'll bet he's never worked on a carburetor.

Not that it means anything, but in the last 35 years that I've been playing with cars I have never seen slant six with a blown head gasket.

dartsport73 said
Im in Columbia Maryland.

Well I'm in Elkton, which is probably a little far for you to travel with it running poorly, but if you want to make the trip I can at least diagnose it for you. I'm also sure there are other members closer to you that would be willing to help.