Yesterday I took the top off the crate to get a better look at the block. Chrysler thoughtfully used only 4 nails to attach the top crate panel, leaving the heads about 1/4 inch above the surface for a nail puller. I guess the intent was for you to remove the top, cut the steel bands, and lift the block out with a hoist. I removed the clear plastic wrapping and verified the block as a 2532630, so it's a poly. I have to say it was pretty cool unwrapping something that was last touched by human hands 52+ years ago.
Turns out it is not actually a short block, as it is missing the crank, cam, and connecting rods. It does have all main caps and the rear seal.
As you can see from the photos, the crate is marked Rexdale, which is a district in Toronto. Was this a Chrysler foundry or a full assembly plant?
The block does have pistons in the bores. Each one is ink stamped on top with either an A or a B. On one bank they line up A-B-B-A, while the other is A-A-B-B. What does this signify?
Dan in Seattle