Selling a running 318 is all about timing. If someone needs it right then, you can get a few hundred bucks out of one. But that's someone that needs a running small block in short order- ie, "my car just broke and I need a running engine NOW and I don't care if its a 318." . Otherwise they tend to sit around and either get scrapped, given away, or sold for super cheap.
I think the steel cranks stopped in '70? I have a '71 318 that had a cast crank in it.
Oh, at Serj, depending on how far you're shipping it, a palletized engine can usually be shipped dock to dock for around 200-300 bucks. Pick up and delivery costs more, especially if residential addresses get involved. I've had an early Hemi, complete from carb to pan, shipped from the Midwest to California dock to dock for under $250. That sucker is HEAVY. But, its less about weight than it is size and how easy it is to pick up and drop off. A palletized transmission costs almost as much as a palletized engine, even though it weighs hundreds of pounds less. But it takes up the same amount of floor space, and still gets picked up with a forklift. Anyway, its not really worth it to ship a 318. They may be hard to find, but they aren't worth any more than the shipping cost.